I'm not sure what you meant by "stock in distros", but I hope you don't mean it comes installed and configured out of the box on all distros, as that is emphatically not the case:
It is stock in Fedora, and it's the "driver" in Ubuntu just that apps are using ALSA/Pulse emulation libs, not the native ones. This has no effect on the BT support. Also, it's just Ubuntu being weird again.
Ubuntu is the most popular Linux distro. If Ubuntu requires workarounds to get audio working, then Linux requires workarounds to get audio working. No whatabouts, no "it just needs one quick thing", if it doesn't just work then it doesn't just work.
