At the end of the day, whatever the source file looks like, you’re turning it into an analog signal in order to make the speakers move. So how is it at all effective?
You can even send a digital stream of the bits over Bluetooth to speakers. So it seems like the ability to decode it is a fundamental requirement for it to be a useful file. So why even bother? It seems like it would be trivial to copy into a different format.
Because before internet was source of media someone invented DVD region locks in the first place, all corporate followed with dividing world to regions and now we’re stuck with this crap. File DRM is just second iteration because the people were already hired, structures were already established so they just build it on the region lock.
https://en.wikipedia.org/wiki/Regional_lockout