

Never ending side channel attacks. Stallman was right, only 100% FOSS gives you control over your device.
And given that a lot of this stuff is relying on timing the only reliable cure is to make everything slow. But no one wants that. Or maybe getting rid of precise timers in userspace. It would be funny if stopwatch precision was bound to screen refresh rate.
I think this intiative is spot on. I would describe current approach of 2 major OS vendors, Google and Microsoft as such:
Microsoft demands standardization at firmware level via UEFI, ACPI etc. because they bring OS kernel and userspace.
Google demands Linux API version and brings just userspace.
In theory Google approach better facilitates open ecosystem but each OEM treats Linux kernel as just a firmware blob so the end situation is actually worse.
On the PC we have standardized firmware while Android chases Linux API levels each release and thus undermines the whole ecosystem.