What is your opinion on Keynesian economic theories?

They eventually come back to bite you in the butt. 

That they don't take environmental considerations into account but besides that they're basically sound.  They were just unlucky enough to have been prevalent when the rich decided to scupper the move towards equality.

They are based on the assumption that people don't spend money they don't have.

That says a lot about "classical" economists

It was an evolution, and it can last to the longer run even when we are all dead already. My admiration goes to the Neo Keynesian model as well. I know that Prof Richard Wolf cannot agree with me. But cooperative economics is almost dead, even in the father land like Germany.

You can be first to open a place on the moon.