To its credit Apple does allow other operating systems to boot on its M1 machines, see the Avahi Linux project, but there is no guarantee that future chips or maybe even future firmware releases, will maintain this.
Remember that the PS3 originally had an OtherOS mode that was subsequently removed.
That is all well and good until the Monsanto seeds begin landing on your own lawn.
With Microsoft’s near monopoly in x86 non-server computing, there are externalities to what Microsoft decides for its home and business desktop users. Unfortunately, what Microsoft decides to do does affect Linux users; especially those buying machines without coreboot. Outside of server equipment, it could become very expensive to ask AMI, Insyde, and Phoenix for Linux-friendly features.
It will likely always be possible to buy hardware that runs Linux, but if you are pushed out of sharing the high-volume home and business desktop market with Windows, things can become expensive, prohibitively so. Not everyone can afford a Talos.
Strictly speaking, no, but we are increasingly in a precarious position. I think the original post’s video (despite its errors) is correct in that owner control of secure boot now is highly dependant on Microsofts whims.
If Microsoft does not require an off switch, what motivation is there for vendors to include such a thing? If it is forced on, then there really is not a way to set your own platform key, and you are potentially locked into Microsoft’s UEFI CA.
That is a solution, unless the the option is removed, and if your CPU has been fused with something like Intel Boot Guard, even manually flashing the boot ROM, such as with coreboot, will be unavailable to give you control.