Certainly Samuelson is not responsible for the The Hicks-Hansen IS-LM Model, which is how much of what passes for Keynes is presented today, from what I have read. But Keynes was careful not to use complex mathematics so as to clarify the assumptions, in part. Nor did he use equilibrium analysis, rather criticizing the economics of his day for being useless in a crash precisely due to being based on equilibrium analysis.

My understanding, based on my reading and on clarifications by Bruce McF, is that in bringing Keynes to US audiences, Samuelson rebuilt his work so as to make it more compatible with US Mainstream Economics, devoted as it was and is to equilibrium analysis. From that point of view US economists who are familiar with Keynes are likely to have a different view of him than would his Cambridge, England intellectual descendants, such as Joan Robinson.

I am coming more and more to the view that the reason Keynes was so thoroughly abandoned in the 1970s is that allegiance to the Friedman approach was, to a large extent, purchased by elites operating through think tanks, through academia and through institutions that handled their money because they did not like the implications of Keynes nearly so much as they liked Friedman and Hayek. Given that bias, any defect in Keynes would suffice to throw him out. Justification of their activities was vastly more important than explanatory power. This possibly overstates the foresight and planing that was involved, at least in-so-far as what can or has been clearly shown, but I still have a lot of reading to do on this subject.

"It is not necessary to have hope in order to persevere."