The crap Apple does with iMessage really should be illegal.
I really miss the days of when I could load all my accounts into Pidgin (Gaim!) and have almost everything centralized. Now I have a teams window (which doesn't bother me too much since it's a work app), a tab for slack, a tab for the umpteenth iteration of whatever Google has decided to call their chat platform, a tab to get SMS messages through google messenger (a welcome change), a window for signal on the desktop, and tabs for Facebook and LinkedIn (both or which I try to never visit, but would like to know if someone contacts my on, and I refuse to load on my phone). I just realized I've apparently abandoned my ICQ/AIM accounts to the past.
That's the desktop. I have almost all those as separate apps on my phone, with separate ways to use them, separate notification preferences, etc.
The instant messaging ecosystem has gone to complete shit, and I doubt anyone that used it seriously before this happened will disagree. And what we got in exchange for every company walling off their own IM system? Honestly, I'm not sure anything that couldn't be recreated fairly easily in a client with a couple months work if someone had extended their protocol to do more.
Me too! I'm very much hoping that matrix - the protocol - continues its steady climb (both popularity and adoption), because that is what i see as the future for that kind of experience where if not everything at least lots/most of my comms interactions will be managed on my side by a single "interface". I'm an admitted fanboy of the matrix protocol (as well as matrix apps like Element, FluffyChat, Quaternion, etc.)...so maybe i'm biased, but have you tried playing around with matrix, and its associated apps, to see if it gets you closer to that older Pidgin/Gaim/Adium-like experience?
(I'm not affiliated with the matrix org. nor any app/client builder, as noted i'm just a fanboy.)
In any other case, it's just the XKCD standards meme[1] all over again, in that it might be better in many ways, but I doubt it will actually help market fragmentation.
1: https://xkcd.com/927/ which actually specifically mentions instant messaging.
The problem OP is alluding to is that some people avoid talking with people who don’t have iMessage, because SMS costs money. So there is a bit of peer pressure to use it, and a lot of people are stuck in iOS because of that.
It’s not that different from Signal/Telegram/WhatsApp, those apps are also closed and rely on network effects. But they are free and work on other OSs, while iMessage requires a relatively expensive phone.
This is doubly true if they have ever used an Apple PC to receive iMessages; in that case it will almost certainly never reach the new phone via SMS.
I don't believe there is a fix to this; sometimes you can repair it on the other party's phone by munging the contact, but most messages will just be blackholed.
Two solutions. The first requires an iPhone (to disable iMessages on your account with) and the other does not. This has been around for years now.
The fact that abuse of standards and customer lock-in is ubiquitous doesn't make it any less abusive.