> There's no way to know GCHQ/NSA aren't running 90%+ of bridges and exit relays
Yes there is. There are currently 857 exit nodes. The Tor Project only has to personally know who runs 86 of them to ensure that 90% of the exits are not run by the NSA.
In fact, since ~90% of traffic exits through the top ~260 relays, they'd only need to know 27 of the people who run those.
This guarantee doesn't scale very well considering the combined 5 Eyes intel budget is ~60 billion USD and throwing just 0.1% of their budget at negating Tor would completely overwhelm the network with hundreds of thousands of stooge relays, plus they have the added benefit of global backbone cable traps. Tor can't give any kind of guarantee against a global passive adversary (5 Eyes) which is why they specifically warn against believing otherwise.
Yes there is. There are currently 857 exit nodes. The Tor Project only has to personally know who runs 86 of them to ensure that 90% of the exits are not run by the NSA.
In fact, since ~90% of traffic exits through the top ~260 relays, they'd only need to know 27 of the people who run those.