Philosophical Brinkmanship
No doubt the powers that be have a vested interest in pushing extreme philosophies. At the risk of starting a fight, I won't throw any of the obvious (to me) extreme philosophies under the bus. But maybe capitalism is a favorite whipping post that does drive a lot of our thinking.
But to your statement, yeah, it's ok to pass through extreme philosophies, but not "exist there".
Is there an agenda to drive us to extreme philosophies... I'm going to vote "yes". I don't think any form of government on earth in history has arrived at the utopia they claim to push to achieve. Not that we should be dismissive of good ideas and lessons learned. That would suggest then that historically we were driven to extremes and collapse was the result.