It's a chicken and egg problem I think. I'm not going to latch on to Google products because I expect them to just kill it in a couple years anyway.

Google kills products because not enough people use them.

If Google keeps Allo/Duo at the front of their messaging apps, adds desktop support to Allo, and keep improving performance/features for the next 5+ years, then it might actually gain a decent userbase.

I use Telegram right now. It Just Works™ for me and the people I talk to. It's fast, stable, and they keep adding features without it feeling like bloat. I also don't feel like I have to worry about it getting abandoned in the next couple years.