Huh, I haven't seen anything like this. I've been on T-Mobile forever. I don't make many voice calls (maybe one or two per week, at most), but I receive a decent amount. I haven't noticed situations where I'll notice a call came in only because it went to voicemail without ringing.

So I don't know. I believe that you're experiencing what you're experiencing, but I'm not sure the cause is what you're thinking it is, because it would be weird for carriers to only deprioritize incoming calls for some subscribers (like you) and not others (like me).

But maybe it's also the case that the cell towers in my area aren't starved for capacity, but they are where you live?