The garbage collector removes all packages/derivations that are not (transitively) used any more. So it is similar to apt-get autoremove. I don’t think that classifies as bloat. You could just regularly run the garbage collector.

Ok, then explain how it works. Where does money in circulation come from?

You realise that debt of the government is equal to wealth in the private sector? Being debt-free would mean that there is no central bank money in circulation. How would this help the actual economy?