Post-Keynesian usually make a great deal of and almost set up a false dichotomy of "Post-Keynesianism" vs Neo-classicism, when in reality the view of equilibrating being a process was alot better known pre-Keynesian revolution.
Entrepreneurship was the hallmark feature of classical economists such as Say and others, and many textbooks included this. It was only until the harmful influence of such writers as John Maynard Keynes, Paul Samuelson, Joan Robinson and others that aggregative and the purely British walrasian view of economics dominated completely. They were of course critiquing it, but in critiquing it they went to far and dropped all nuances of different authors.
"AEN: But if a neoclassical economist told his class about Kirzner's theory of entrepreneurship, that would be an improvement.
[Israel] KIRZNER: Certainly, given today's rigid environment. Once, however, I gave a talk on the Austrian view of the market process, and the late Abba Lerner was there. He said that what I was calling the Austrian view is precisely what he had been taught in school and had long accepted. I'm sure it's true. The perfectly competitive model was never dominant in neoclassical economics until E.H. Chamberlin and Joan Robinson brought us imperfect competition. Then, they retroactively attributed perfect competition to those that preceded them."
The book is called "The Economics of Imperfect Competition"(1933) and "The Theory of Monopolistic Competition" (1933).