DirtyDan I've been trying to get people to use Signal for over 7 years for day-to-day messaging with me and have only brought over 3 people. And all of them still complain about having it installed and having to use it every chance they get.
I've been trying to get people to use Signal since before it was even called Signal. Remember TextSecure and Redphone? It's been practically 15 years. The amount of resistance has been amazing. People will install every ridiculous candy crush whatever app on their phone, but when you ask them to use Signal suddenly they suddenly can't stand the idea of another app on their phone. Also they complain endlessly about it not working exactly like iMessages, because reactions and message editing and whatever are so important. I mean, I just want to send messages. Other people live and die by emoji.
For years and years, the only people I could get to use it were one friend, who seemed interested in the privacy angle, and my mother of all people (because she's just nice and easy going and was like, okay sure whatever). Honestly, my completey non-techy mother has been ahead of all the nerds for a decade.
It's only been in the last two years, and especially the last year, that suddenly a lot of people in my contacts have been popping up on Signal. A lot of people in the U.S. are freaked out now about what's going on politically. Amusingly, usually when I travel abroad people want me to use Whatsapp, which I refuse to use (because Meta). But when I was in Berlin a few years ago, a friend there, without my saying anything, wanted to set up a group chat and told me she uses Signal, because that's what everyone there uses. It was amazing to stumble into a place where Signal is actually the norm. For obvious reasons, Germans place a high value on privacy.
Honestly, all of Google's and the carrier's "verification" checks that break RCS are so dumb. Signal does not do this. It just works. For the sake of "verification" Google is breaking the security and privacy people could have with RCS (at least between Android phones for now).