Blame Stalin on the myth of 'centralized planning' or whatever Marx dreamed up about more advanced forms of government. It was a pipe dream, because government is made up of people. And selfish, brutal sociopaths keep bubbling up into government. So the more control govt has, the more Stalin's we'll see.

I'm fairly certain capitalism in its current form isn't sustainable (cf Piketty), and I don't think government is intrinsically sociopathic.

The open question is if government with checks and balances is stable in the long term, or if it will fall apart and have one branch take over. Time will tell.

Piketty's arguments are cherry-picked. No, I haven't read the book, and no, I'm not going to take the time to look up sources for you.

First, I am in a strong position to talk about philosophy.

Second, Marx made Stalin possible by setting up the necessary intellectual framework of class struggle, capitalism as oppressive, dialectical materialism (denial of reason and free will), etc.