This is the big one IMHO. Apple is all about control of the stack, top to bottom. Any sort of "help" with linux on macos would be threatening to that control. Apple "helped" even more than I would have expected by not locking alt OSes out of the bootloader. Probably for less than altruistic reasons, but they did do it.

loss of control, fewer services sales w/o their built-in upsells etc… tragedies

Go team Asahi!