Earlier quoted context omitted.
If there is still one company pushing their own strongly opinionated client, how does having competing options available to power users detract from that? Like I'm not saying Signal-the-client should go away, rather that Signal-the-company who runs Signal-the-server could be accepting of third party clients, to the point where Signal was easily usable from F-Droid and whatnot. How would that undermine the mass market…
They do accept third party clients. They don't like it, but they don't have a choice, because they don't use device attestation.
The last I heard there was a "desktop client" but it was actually going through the mobile client. This could be out of date, although I haven't seen anything directly refuting it and I haven't bothered to dig.
To the original point, the proprietaryesque policies rooted in the authoritarian desire for centralized have severely hampered my interest/adoption, and I still don't see how policies disrupting the libre ecosystem in any way encourage adoption in the non-libre ecosystem.