This isn't really unique to Apple Silicon. The difference here is that most proprietary systems Linux has to work with on PC were reverse engineered many years ago, while AS is being reverse engineered today.
The Asahi Linux developers themselves have praised the openness of Apple Silicon, not because they have access to documentation or source code that we don't, but because it seems Apple has gone out of their way to make sure their platform can securely accommodate third party operating systems even though they have no incentive to. It's surprising in contrast to Microsoft, who has been slowly trying to make booting Linux on PCs that ship with Windows harder and harder.
I definitely think calling Apple Silicon an "open platform" is a bit of a stretch, but it's not the iron clad walled garden people think it is either.
> The difference here is that most proprietary systems Linux has to work with on PC were reverse engineered many years ago
Such as what, though?
Intel and AMD both wrote support for their systems themselves. Nvidia has long offered a proprietary driver for Linux users, and even Intel Macbooks were a shoo-in once the firmware is sorted out. It's been a long time since someone has approached a full-scale reverse engineering project like Asahi, and I think characterizing it as "non-unique" undersells the amount of bespoke work here.
Apple made the right move by continuing to allow third-party OSes, but that's not equivalent to building out support. The work required to bring up a black-box SOC is hugely distinct from using first-party drivers to boot into Linux through UEFI.
Drivers for WiFi, audio, Bluetooth, a heap of I2C devices like keyboards on laptops and temp/fan control, graphics cards, and much much more.
Not a single company “built out support” for all these things. And none of it is covered by some common interface — each must be reverse engineered (or implemented following reference manuals, if they are available). Intel and AMD did not provide support for these, because they can’t — the processor architecture is oblivious of these peripherals.
I think you’re underestimating how much volunteer work has been done to get Linux to be usable on any machine. From your wording, I suspect you may think there are some grand unifying abstractions that, when implemented once, provide compatibility with most machines, and that Intel and AMD did just that. But that would be mistaken.
I'm comparing it more to the state of Linux on PC in the '90s and early '00s, when most vendors didn't care about Linux unless you were buying a server. Getting Linux running on a laptop back then was often a mess of hacky reverse engineered drivers, sometimes with incomplete or missing functionality.
Of course what Asahi Linux has undertaken still feels like a bigger and more impressive task, I'm just saying that this kind of work is not entirely unprecedented. The current Linux ecosystem on Apple Silicon is more comparable to that of the PC Linux ecosystem from 25 years ago than from today.
The Asahi Linux developers themselves have praised the openness of Apple Silicon, not because they have access to documentation or source code that we don't, but because it seems Apple has gone out of their way to make sure their platform can securely accommodate third party operating systems even though they have no incentive to. It's surprising in contrast to Microsoft, who has been slowly trying to make booting Linux on PCs that ship with Windows harder and harder.
I definitely think calling Apple Silicon an "open platform" is a bit of a stretch, but it's not the iron clad walled garden people think it is either.