If I accept that using PGP manually is acceptable for getting wide-spread encryption then you're right, but the fact is that tech people rarely use it because it's so cumbersome that the chance of normal users using it successfully, let alone using the terminal these days, is so slim that it's basically absurd to think that is the way we're gonna get wide spread encryption.
I don't want to only talk to my tech friends. My best friend runs a small business doing nothing to do with tech and when I talk to him I want to be sure no one else can read/listen to what we're saying because it's private. There is no version where my friend learns to properly use PGP consistently so we can talk that way. The only reasonable way is WhatsApp or Signal.
Given the absent security of desktop Linux, and the dreadful opsec of its users, as revealed by many cryptocurrency wallet thefts, I wouldn't place much trust in persistent PGP secrecy unless all participants used Heads, and renewed keys regularly, and ran nothing except gpg. How many people do that, in the entire world, do you think? A hundred, at best?