Keynes died in 1946, so he may not have the end all answers to contemporary economics, but he was more right in his lifetime than anyone has the right to be. And his ideas are certainly better than the Austrian and neoliberal ones that followed.
Except that Austrian ideas were around before (Menger and Bohm von Bawerk in the 19th century) and were gaining strength contemporaneous to Keynes. You may know of the Hayek-Keynes rap battle YouTube video.
It was the smearing of classical liberalism as being the cause of the depression - when it was plainly not - as well as the forces of the left rising in the 1930's that saw the Austrian school fail to win many converts despite predicting the Depression which is something that Keynes whiffed on. Austrians were able to also explain stagflation of the 1970's - something that Keynesian & neoclassical followers had a tough time getting around.
They were never discredited, it just went underground in the pre-war years. Having socialist economic policy-friendly fascists who absolutely hated classical liberalism about as much as they hated Jews did a lot to break up the original movement in Austria. Especially when the leader of the movement, Mises, himself was Jewish. Then alongside but not entirely in lockstep with the rise of the new post-war conservative movement the Austrian school saw a new flowering in the 1960's and early 1970's alongside the Chicago school led by Milton Friedman.
The Keynesian views, flawed as they are, fit in with the idea of increasing state power so of course your lot will prefer it. The Austrian views fit in with the idea of decreasing state power so they were at odds with both the socialist and nationalist views that predominated in the 1st half of the 20th century.
Thus any tenuous connection to the Austrian school is a guilt by association thus Margaret Thatcher's record despite not following the tenets of classical liberalism is considered a black stain on Austrian economics.
I guess if you want a large corporatist economy working hand in hand with a large bureaucratic government then Keynesianism is perfect even though the model has so many assumptions that put it so far from reality.
It all fits in together quite well with interventionist Wilsonian democracy abroad. Intervention by the government with fiscal policy as per Keynesian economics, intervention by the quasi governmental Federal Reserve in monetary affairs. Both together have a mission to manage the economy (looking at inflation & unemployment). Now we've seen our debt go to 20T and the deficit is a hellish $666B - and a ruinous crisis ten years ago. Yet we're still going to the same well.
It's disheartening.