While this is not correct, and I do use my BT headphone with Ubuntu 20.04, it's is almost true for any casual user.
Indeed, the number of glitches and irritating workaround I have to use to make something else than a mouse work with BT is something most people don't want to put up with their $1000 laptop.
Yes, BT is a shitty tech. But their phone works out of the box. Their Mac OS and Windows as well.
The fact we still get BT not pairing randomly (or wifi stop working, or sleep mode never awaking) is a huge problem in 2021.
We should not ignore that as a community.
That's why I report bugs, give money and help people online.
But it will not be enough if we close our eyes on the work yet to be done.