Fukuyama famously declared that history ended in 1989. Not in the sense of events ceasing to happen of course. Basically what he meant is that the American way (capitalism + republican democracy) had been vindicated as the only legitimate and just way to run a society, now that the Soviets were no longer deeply committed to socialism and failed to intervene in eastern Europe and East Germany.
A few years later a tangential theory, the "McDonald's Theory of Peace" came around. Ironically it was proven wrong even before it was formulated since America invaded Panama which had a McDonald's, but the basic idea that capitalist democracies don't go to war against each other is still popularly believed.
Do historians still take Fukuyama's triumphalism seriously? It seems like it would be hard to nowadays with a more belligerent Russia, the fact China is still just as autocratic (if not more) than it was in the 80s despite becoming more market-oriented, and seeing that fascism is making a comeback in India and Greece.
Evaluating something like the end of history thesis is really something better suited to political scientists than historians. But even if you read Fukuyama's more recent works (Origin of Political Order/Political Order and Political Decay), you'll notice that he's not very bullish about capitalist democracies. One of his main thesis in the two books is that there's a big difference between a democratic state and a capable state and that democracy does not necessarily lead to a high standard of governance. He specifically writes about China and attributes its success to having an institutional history of a meritocratic bureaucracy and "high quality autocratic rule" while at the same time pointing out the dysfunctional Indian political system.
Fukuyama nowadays seems to believe that there is a kind of crisis with democratic governance, especially in the United States.