The hard part is getting the people you want to establish a trust relationship with to give you a copy of their key. Web of Trust was the answer to logistical key distribution problem. The idea being there would be an organization that would vet people and vouchsafe their cryptographic material for everyone else.

The problem of course, is that the more invisible this is to users, and the more unintuitive the actual mechanics, the more valuable cracking the CA's becomes for hostile actors because of the ensuing blast radius compared to the boast radius that would result from theoretically getting the practice of key exchange in the public, and getting them to internalize the act of creating their own trust networks.

Of course, if you have dreams or fantasies of being able to control people, none of the work that goes into educating the populace is ever going to be endorsed, because once everyone realizes that they can at least assure their own safety by not delegating their cryptography, the entire idea of eacesdropping as a third-party by tapping the line is unmade. Which is not a popular state of affairs universally.