Capture of mining power by bad actors is my greatest fear for Bitcoin. If the cantillionaires plow enough of their wealth and influence into capturing mining power they could control a huge percentage and undermine the network in many ways. It could already be happening for all we know.

A vast majority of mining power is in the US and China, arguably the countries with the most to lose from a Bitcoinized world. The large mining companies are vulnerable to takeover, by violent or economic means, and in fact may already be "sleepers" waiting to act at a certain time when Bitcoin becomes the most threatening to them.

I can imagine a scenario where the fiat shit is hitting the fan and Bitcoin is poised for a leap forward in adoption. That is when they will spring the trap and undermine the network in some way, which could test confidence in the Bitcoin network. If they can suppress the price during this time it could drive legitimate miners out of business and allow them to consolidate control over mining power.

Idk, maybe I'm giving them too much credit.