Schumpeter is interesting. He sees a development of capitalism to the point where the key positive characteristics (competition, entrepreneurship) become limited by institutional powers, especially (ironically) large capital which seeks stability more than profit and mass democracy in the welfare state. The two elements merge in advanced capitalism thus leading to minor variations between social democratic and liberal democratic parties.

And excellent follow-on to Schumpete is Habermas' Legitimation Crisis (although the original German title - transliterated as "Structural Problems in Advanced Capitalism" is superior).