I mean that at least relatively speaking, nobody[1] uses OpenPGP for messaging, so it's not a threat to Signal's market share. Which is presumably the implied motive for Moxie to trash talk OpenPGP.
[1] I can admittedly think of two people I know for whom I could probably find public keys and who would probably be able to decrypt a PGP'ed email if I were to send them one, but they're both Debian maintainers who I met via IRC. Whereas I have maybe a couple of hundred people on my phone from various walks of life I could send Signal messages to with literally no extra effort.
> Which is presumably the implied motive for Moxie to trash talk OpenPGP.
I'd rather say that Moxie implies that OpenPGP is broken beyond repair and thus the only alternative is his centralized solution. While he doesn't say this explicitly his other post (The ecosystem is moving) says exactly this.
Your anecdotal evidence while interesting does not show that OpenPGP cannot be improved, only that given enough government funding you can build a nice centralized, encrypted solution but as the top comment by lmm shows [0] it's not clear what audience is Signal aimed at:
> There is no threat model where Signal makes sense.
[1] I can admittedly think of two people I know for whom I could probably find public keys and who would probably be able to decrypt a PGP'ed email if I were to send them one, but they're both Debian maintainers who I met via IRC. Whereas I have maybe a couple of hundred people on my phone from various walks of life I could send Signal messages to with literally no extra effort.