And what these companies are doing is making the (hardware or external) functionality dependent on that copy-written computer program. So now it's impossible to modify your device without modifying software and thus breaking copyright.
Take a look at the US constitution copyright clause:
[the United States Congress shall have power] To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.
How does this use case of copyright promote the progress of science and useful arts? Copyright was clearly intended to make it temporarily difficult to publish information, not to make it impossible to modify machines.
But regardless of whether they should have that say, they empirically do seem to have it.
Which is why the solution is free software, and why the FSF has always understood the threat of hardware and encryption being used against the user rather than for them.
In the USA, you have things like the first sale doctrine, which applies to things like books and audio recordings, but DOES NOT apply to software, especially not software that makes use of services provided by the author (as most mobile apps do). Do not expect, in general, to have a right to use a piece of software, especially a mobile app, in ways not explicitly authorized by the app's vendor. Yes, this also means video games as things you can play forever are going away. Get used to it.
users should, that's why feedback forms exist