the listed examples all exist. signal is already more widely used than pgp ever was in the last 25 years.
> ..., apply some multiplier, ...
You glossed over that like it was nothing. Let me rephrase GP: "... with no possible way of knowing the multiplier".
Obviously there exist k such that for n keys on "the keyservers" (we'll have fun enumerating those too) and s signal users, k*n > s.
"I also do not recommend using a centralized service that keeps your keys on a smartphone. However I warmly recommend using the Signal Protocol whenever messaging is to be done. Signal can be a direct replacement for PGP someone just has to code up the whole thing (time to flesh out signal-cli)."
Can be, someone just.