Cell service is a commodity, though. They effectively act as dumb pipes for sound and data, and although they would like very much to not be that anymore, that is the reason they have customers. Also, there aren't many value-adds to be had at the protocol level. Everything else was already fairly standardized, so adding the number porting stuff on top of that was comparatively easy.

What we're talking about here is pure software interop. There is no standard, and any standard that would be devised would become a quickly-outdated albatross around the neck of the developers. Imagine writing code to interface with someone else's crap API, except now you're required to do it by law, and any new feature you come up with has to be either shoehorned into it, or more likely, go through a long and bureaucratic approval process, or even more likely, simply never shipped.

Now pretend instead of Facebook, it's your instance of Mastodon that you want to hack on. HN doesn't have the requisite font face options for the magnitude of NO F'ING WAY that is my reaction to getting the government this deep into the nuts and bolts.