Tri-screws (Nintendo), were one of the first things I had to buy "single-use" screw-drivers for.
This makes sense to me since "security screws" are an almost entirely useless form of tamper prevention or tamper evidence. However I've no idea what the real story is.
I'm wondering if somebody with knowledge can chime in....
Although Apple uses odd security screws in all their products, their pursuit of thinness and compactness also probably leads them to need precisely manufactured small parts.
Of course if the Mac Pro had just used the old Mac Pro design or the previous Power Mac tower designs, perhaps the parts for a tower case might have been easier to find...
The "right to repair" movement and subsequent legislation was squarely pointed at Apple. There's simply nothing Apple won't do to stymie user rights, from purposefully forcing app-devs into the app store by crippling the iOS browser, to retroactively modifying app store rules to kill competition (as with Steam), to making it next to impossible to repair hardware outside their store