I understand that (IIUC in Matrix the client decides what push gateway to use, and the Element client just hardcodes matrix.org and lets anyone use it for free), but it doesn't really do much for my practical concerns. I'm looking for something my users can tolerate (which means no monthly fee) and that I can be reasonably confident won't rugpull us or vanish in the next ~10 years.
I guess my question is, what makes you confident that Element won't change the terms under which people can use their push server?