Despite the awful UI, Skype serves me very well and I think they are improving quickly on Linux.
The problem is none of my friends/family use it. Some have it installed but they always use something else for chatting.
Nobody I know uses Signal.
BTW what is so awful about Skype Lite interface? a bit more cluttered than Viber, WhatsApp or Signal, but still ok compared to Messenger nobody has problem with judging by popularity
The reasons I hope Google gets their act together is because they are in the right place to do so. They have the mindshare, just need to execute better and network effects may kick in. It also doesn't matter if they have the best platform but none of my friends/family use it. Again, Google is better positioned to make that happen, IMHO.
I don't know what Skype Lite is. I use Skype for Linux Alpha. Is that it? It seems to be missing video calls, the chat interface is complicated (spent some time trying to find the chat while in a voice call), it doesn't integrate well with the desktop (it minimizes when I close, instead of hiding in the tray). Like I said, they are improving.
As for Signal and converting people to some technology I know is better... Sorry, tried that too many times. It's not worth the time invested. These companies will have to figure out how to increase their market share without depending on tech enthusiats.