No I agree you can't prove they are distributed, but I don't see the threat as realistic. I also think the only reason for someone to take a controlling stake a

No I agree you can't prove they are distributed, but I don't see the threat as realistic. I also think the only reason for someone to take a controlling stake and attack the network would be to kill Ethereum and make everyone lose confidence. Bitcoin is susceptible to the exact same attack, someone could build or buy enough mining power and cause a huge reorg to wreak havok. I take your point that Bitcoin could more easily recover from this, as new mining hardware can be built by honest participants unlike tokens, but it would take too long. It would be too late to restore confidence at that point anyway. I think both networks are resistant to the attack for the same reason, it's just too expensive. You could argue that Ethereum is actually more resistant, as buying tokens drives up the price. Bitcoin has the opposite economies of scale. The more chips an attacker produces, the better they get at making them, and the more cheaply they can amass hashrate.