Considering the demographic polarization in China’s urban system over the past three decades, this paper develops a comprehensive quantitative spatial equilibrium model to clarify the centripetal agglomeration effects, centrifugal commuting costs, locational fundamentals, and migration frictions on urban scale and the evolution of the urban system. The findings from theoretical model deduction, structural estimation, and counterfactual simulations indicate that improving commuting conditions or reducing migration frictions will lead to sustained population growth in mega and larger cities, resulting in a more concentrated urban system distribution. The equalization of agglomeration effects significantly drives population growth in small and medium cities, encouraging the urban system distribution to evolve toward a more uniform pattern. The amenity or productivity equalization of locational fundamentals will support population growth in small and medium cities, and eliminating inter-city housing price disparities will enhance the population size of mega and larger cities. Counterfactual policy evaluations show that a uniform distribution of the urban system promotes social equity but reduces overall social output, whereas a concentrated urban system distribution increases total social output but may hinder social equity. Therefore, this paper aims to balance efficiency and equity by proposing that, in the future, China’s urban system should adopt a structural optimization path of stabilizing both ends while promoting the middle. This approach emphasizes the social equity of peripheral small and medium cities and the economic efficiency of super cities, focusing on the development of small and medium cities within metropolitan areas and urban agglomerations. It seeks to transition the urban system from a dumbbell-shaped structure to an olive-shaped structure, fostering a coordinated development pattern among large, medium, and small cities.

Investigating the regional linkage effects and their transformation mechanisms from the perspective of high-quality economic development aids in comprehending the overall patterns and linkage dynamics of regional economic development in the new era. This offers a crucial theoretical foundation for effectively regulating regional linkage effects to achieve coordinated regional economic advancement. By quantitatively identifying the regional linkage effects of high-quality economic development in China, this paper examines these effects and their transformation mechanisms through a framework encompassing four major regions. The findings reveal that China’s high-quality economic development level demonstrates significant regional economic characteristics, with radiation-driven effects already emerging between the eastern and central regions, as well as within the eastern and western regions. Factors such as population mobility, the establishment of special economic zones, and the reduction of green development gap all contribute to the shift in regional linkage effects from siphoning effects to radiating effects. To enable underdeveloped provincial-level regions across various regions to benefit more from radiation-driven effects, the central and northeast regions should prioritize internal regional dynamics; the western region should enhance population mobility and the role of growth poles in facilitating the transformation of linkage effects; while the eastern and central regions should focus on the constraining effects of green development gap on the transformation of regional linkage effects.

Based on the three-region local spillover (LS) model extended by new economic geography, this paper theoretically analyzes the formation mechanism, structural characteristics, and spatial evolution of urban agglomeration innovation centers. It subsequently conducts an empirical test on the Yangtze River Delta urban agglomeration, recognized for its strong innovative urban agglomeration attributes. There are four findings. (1) The cyclical accumulation of causality underlying urban agglomeration innovation centers is rooted in the accumulation of knowledge capital. As knowledge capital aggregates, urban innovation costs gradually decline, thereby fostering the endogenous agglomeration of knowledge capital. This cycle repeats and ultimately facilitates the formation of innovation centers. (2) The spatial spillover of knowledge capital serves as the primary driver in establishing innovation centers. Variations exist between local and cross-regional spillovers of knowledge capital across different regions of urban agglomerations, further reinforcing the “innovation center-peripheral city” structure. (3) The interactive innovation within urban agglomerations is characterized by knowledge spillovers from the innovation centers, which solidify the “agglomeration” structure, while the absorptive role of peripheral cities enhances the competitiveness of the “center,” ultimately improving the overall welfare of the urban agglomerations. (4) In the Yangtze River Delta urban agglomeration, home market effects and knowledge capital spillover effects support the establishment of innovation centers, while market crowding effects exert a restraining influence. The development of urban agglomeration innovation centers is a crucial cornerstone for advancing national innovation-driven development strategies and optimizing the innovative development framework of urban agglomerations. This paper offers new perspectives on addressing the siphoning effect of central cities and optimizing the allocation of innovative resources, while also providing a theoretical foundation and decision-making references for establishing innovation systems and urban agglomeration innovation centers.

Enhancing the basic role of consumption in economic development is an important way to enhance the endogenous stability of economic development and to promote high-quality economic development. The focus of economic development has shifted from production to consumption, the stage of economic development has shifted from supply constraints to demand constraints, the economic development strategy has shifted from export-oriented to the new pattern of dual circulation, and the economic development model has shifted from extensive growth to high-quality development, which has promoted the transformation of economic development momentum from an investment-led economy to a consumption-led economy. Consumption plays a fundamental role in economic development, and matched production, equal distribution, and smooth exchange provide conditions for consumption to promote economic development, which is a typical feature of a consumption-led economy. China is generally in the primary stage of a consumption led economy. To promote the transformation of China’s economic development momentum, it is necessary to match the economic development momentum with the economic development stage and promote the adaptive transformation of the economic development momentum from an investment-led economy to a consumption-led economy.

Since 1949, regional economic development has predominantly progressed through four stages: low-level balanced development, unbalanced development, coordinated development, and high-quality coordinated development. Since the 18th National Congress of the Communist Party of China in 2012, China has implemented a range of national strategies aimed at promoting coordinated regional development, including coordinated regional development strategies, major regional strategies, the functional zoning strategy, and the new urbanization strategy. The integration, interaction, and coordination of economic development across regions have continued to strengthen. Grounded in the fundamental principles of Marxism and the practice of regional economic development in China, China’s coordinated regional development theory with Chinese features has emerged, concentrating on addressing the challenges of unbalanced and inadequate regional development in China. Its core essence is to reduce regional disparities, with the fundamental requirements being the equalization of basic public services, relatively balanced infrastructure accessibility, and generally comparable basic living security levels for the population. Mechanism innovations, such as enhancing top-level design, constructing efficient transportation facilities, establishing sound coordinated regional development mechanisms, optimizing the equalization mechanism for basic public services, and improving regional policy regulation and early warning systems, are vital for further advancing coordinated regional development in China.