So my son and I undertook an interesting project of sorts a few months ago... We attempted to obtain bitcoin while remaining completely anonymous. The only way that I could see to successfully do this was to either purchase directly from someone using cash via Craigslist or the like, exchanging a good or service directly with someone for bitcoin or mining of course.

To me using cryptos as a derivative of existing fiat is the weak link in the chain as the anonymity all but goes away. And when that goes away the concerns you've stated reappear because decentralization is gone.