I remember the 'bad old days' in the 90ies when all the big companies had their own chips. SGI Mips, DEC Alpha, HPUX on PA-RISC, Sun SPARC, etc...

I really hope we don't go back to that. Especially with a company that defaults to 'proprietary' for so many things like Apple.

Is anyone else besides Apple doing this?

Microsoft is doing the same thing with their Surface tablets (https://github.com/linux-surface/linux-surface) and no one bats an eye.