You're partially right, but that is because many governments are engaging in Austerity instead (which is worse, quite frankly).
The only things that kept the $850 billion dollar stimulus from working better than it did are 1) half of it was tax cuts, as opposed to infrastructure and 2)$850 billion wouldn't have been enough in the first place (estimates have shown that 1.2-1.4 trillion would have likely been sufficient).
Keynesian economics are responsible for the fastest economic recovery in the history of the world (New Deal, the Great Depression), Monetarist economic principles ended inflation by inducing both the depression and recovery in the early 1980's, Keynesian and monetarist principles were used in Japan's "Lost Decade" (although it took them quite a while to actually spend enough to get out of their recession, after the first round of legislative acts it took them until 1998 to spend more... a couple of years later they recovered and have been considered one of the best economies in the world.. until massive waves ofc).
Where has classical economics taken us?
It just seems everywhere I look, the evidence is there for Keynes - but there is nothing supporting neo-classical policies as a way out of recession(many key principles are essentially frauds... Trickle down theory? debunked.. cutting taxes increases revenue? debunked...).
I've read most of your examples and like most economics it uses the past and is not neccesarily prudent from a common sense standpoint today. Let's give you the benifit of the doubt and say that Keynes worked. Now, do you think it will work forever? Today? 50 years? 1,000 years? Does it work in every situation? Things change.
We can both agree that the world is a much different place today. My problem with Keynesian economics is that it is a justifying excuse for poor choices by politicians. Let's consider the world today and what has changed.
1) Massive foreign debt
2) Scale of debt
3) Global marketplace that reacts to the scale of debt
I would agree that a financially healthy gov can improve a recession by pumping "good money" into the system.
However, common sense will dictate that a financially distressed government that acquires bad debt on top of bad debt is bad. Unfortunately, when you are at the end of your rope, you have to tighten the belt.
It would seem right now, we have Robert Earl Keensian economics as the road goes on forever and the party never ends
This time around ya'll can drop the community organizer tag and refer to his 4 years as a President 
