The neoliberal school of thought has and had significant failings. Still, I think the primary cause of its declining fortunes is that, as tends to happen with once-ascendant political tendencies, it had a lot of successes. The most persuasive neoliberal ideas have become conventional wisdom. The netroots shares the neoliberal critique of interest group brokerage as a model of party-building. Absolutely nobody nowadays makes the sort of arguments that you heard from the 1980s-vintage left about the possibility of winning elections purely through increasing voter turnout. And a lot of the low-hanging policy fruit has already been implemented. Nobody thinks TANF will be re-reformed as an open-ended entitlement. Nobody thinks NAFTA will be rescinded. Nobody thinks we're going to re-regulate the airlines or restore the government-sponsored telephone monopoly. I even think people have privately reconciled themselves to the fact that race-based affirmative action is going to fade away. And so on and so forth.
But did these things achieve any of the desired goals? Presumably the "liberal" part of neoliberal meant something. Welfare reform didn't magically reduce poverty rates. NAFTA didn't make poor Mexicans less poor. The steady erosion of race-based affirmative action hasn't ended discrimination.
So, yes, neoliberalism succeeded in enacting a bunch of conservatarian policies. But now what?