One can absolutely create a society where public ownership is the principle aspect of the economy without being a fully developed Capitalist country. “Full-development” itself is a misnomer, anyways, as analysis of Monopoly Capitalism has shown, Imperialist countries actually become less industrially developed, and would need to develop more, meaning over-development of Capitalism actually becomes a hinderance.

Moreover, we have seen Socialism works in the real world. Countries like the PRC are regularly making massive improvements while western countries sink and decay as Imperialism dies. Markets can be a useful tool, sure, but markets can exist in the context of an economy driven by public ownership, meaning Capital isn’t a major risk of overthrowing the system. Again, lessons from China.