This is an extremely interesting and important question. In the past years, critics are increasingly proclaiming that neoliberalism has come to an end, or at least become too broad or too vague to be used as an explanatory term.
Yet, neoliberalism has proven to be remarkably resilient. This, as Jamie Peck has argued, may be due to its propensity to ‘fail forward’, that is, perpetuate rather than correct or reverse the mechanisms that led to its failures in the first place – the economic/fiscal policies following the 2008 economic crisis are a good example. Or it may have to do with what Boltanski and Chiapello have dubbed ‘the new spirit of capitalism’, meaning its capacity to absorb political and societal challenges and subsume them under the dominant economic paradigm – as reflected, for instance, in the way neoliberalism has managed to coopt politics of identity.
But the success of neoliberalism has arguably less to do with its performance as an economic philosophy (at least after 2008, that is patently not the case – even IMF has admitted that neoliberal policies may be exacerbating inequality), and more to do with what seems to be the consensus of political and economic elites over its application. Neoliberalism allows for the convergence of financial, governmental, military, industrial and technological networks of power in ways that not only make sustained resistance difficult, but also increasingly constrain possibilities for thinking about alternatives.
This is not to say that heterodox economic ideas are lacking. Alternatives to mainstream (or neo-classical) economics range from Marxist and Keynesian approaches, to post-Keynesian, participatory, or 'sharing' economies, and the philosophy of degrowth. Yet, in the framework of existing system of political and economic relations, successfully implementing any of these would require a strong political initiative and at least some level of consensus beyond the level of any single nation-state.
In this sense, the economic philosophy to succeed neoliberalism will be the one that manages to capture the ‘hearts and minds’ of those in power. While the Left needs to start developing sustainable economic alternatives, it seems that, in the short term, economic policies will be driven either by some sort of authoritarian populism, (as for instance in Trump’s pre-election speeches), or a new version of neoliberalism (what Will Davies has called “punitive” neoliberalism). Hopefully, even from such a shrunk space, alternatives can emerge; however, if we are to draw lessons from the intellectual history of neoliberalism, they will require long-term political action to seriously challenge the prevailing economic order.