I want to get off Google products for many reasons, but the main reason is becoming that I can't trust them to listen to users.
How long have you been working on it? What's the exit strategy look like? How big is the team currently?
I noticed that your blog hasn't updated in over two years, while I recognize that making blog posts is time-consuming, when it comes to software that just gives the feeling that the author has abandoned the project. Maybe consider linking to an area you still frequent?
Based on https://gitlab.com/ossguy/sgx-catapult/commits/master and https://gitlab.com/ossguy/jmp-fwdcalls/commits/master it looks like I've been working on JMP's codebase for a little over 13 months now. Prior to that I worked on JMP's precursor (see https://github.com/ossguy/sopranica - also called "Phase 0"), which started about 4 years ago, and was more part-time.
Since I and a lot of my friends depend on JMP for their everyday communication, I'm not really interested in "exiting". If the project were to be sold, it would have to be to someone who cared about keeping the software free and open source, and who wanted to keep it on a federated network. I suspect going public would be a bad idea, because most of the public (i.e. investors) doesn't(/don't) care about JMP's values.
We publish an update on JMP and related projects every 1-2 months. We recently started using Mailman so you can find the past couple updates at https://soprani.ca/cgi-bin/mailman/listinfo/jmp-news and signup if you like. For day-to-day updates, you can join our group chat at https://email@example.com (more options for joining are at https://jmp.chat/#support , including directly from your XMPP client). That's where the majority of project-related communication happens.
And if that happens, likely someone will setup another instance and keep the same service running. That's another great advantage of JMP over Google Voice: all the code is free and open source, so anyone is free to run their own instance if they like. In fact, you could run your own instance right from the start and then be in complete control of whether JMP keeps working for you.