Good question. I think my perception is that finding and using them is a high bar of entry.

And the suspicion that Google doesn't do even a cursory examination would put me off of using anything that isn't independently vetted.

As a Firefox extension user myself, it is pretty crazy what permissions we allow from them. Even with something like uBlock Origin, which I'm sure a lot of people here use, one of the permissions you have to accept is literally "Access your data for all websites". Why are we okay with that?