Having a few vaults with security guards is a great deterrence as the reward is little for the high risk. Having many vaults with security guards draws a bit more attention...
I’m having trouble understanding what you’re saying.
You’d think we’d be better off even with the higher attention, were it to exist, because the level of attention going into making FIDO2 as secure as possible would scale with its userbase. Same with any other security solution being implemented.