From their FAQ page[1]:
> We will eventually release a remix of Arch Linux ARM, packaged for installation by end-users, as a distribution of the same name. The majority of the work resides in hardware support, drivers, and tools, and it will be upstreamed to the relevant projects. The distribution will be a convenient package for easy installation by end-users and give them access to bleeding-edge versions of the software we develop.
As distro maintainers, it is their job to make sure the applications they package work on the hardware they support. This includes submitting patches upstream when that is not the case, as application maintainers likely wouldn't want to support such a niche environment directly. So, yes, they rely on volunteers to fix issues, but they will likely have to support many applications themselves.
There is still a lot of broken software, as this list[2] is surely not exhaustive.
Regardless, all this amounts to less choice of software for the user. The Asahi team has already decided to stop supporting Xorg, and say what you will about Xorg, there will be many applications they realistically can't or won't support for whatever reason.
> Same deal for any other hardware manufacturer. [...] Really not much different to other hardware manufacturers since Linux started.
No, it's very different. First of all, the amount of Linux hackers who volunteered to reverse engineer the wide variety of hardware was orders of magnitude larger than the Asahi team. Even if they limit the amount of devices they support, modern computers are far more complex than in the early days of Linux. Regardless of how talented the Asahi team is, maintaining all the hardware of a modern computer is a sisyphean task for a small group of volunteers.
Secondly, hardware manufacturers could see the benefit of getting their hardware to run in Linux, and many eventually took over support from volunteers. Apple has shown no interest in doing so, and has historically been hostile to open source.
> Asahi devs have made it clear that Apple has chosen to avoid blocking installation of other operating systems.
The fact they allow installation of other operating systems today, doesn't mean that this decision couldn't change in the future. Services are a large part of their business, and allowing a group of hackers to use their hardware without being part of their software ecosystem may seem like a non-issue today, but if this group grows larger assuming projects like Asahi are successful, this might become a considerable loss of income which wouldn't be in their best interest.
> Apple has no issue with it.
Can you point me to an official ackgnowledgment of Asahi Linux by Apple? Or any indication that leaving this door open was a sign of good will, instead of a lack of interest in closing it? What makes you think they wouldn't eventually lock down Macs in the same way they do iPhones and iPads?
> ARM is a stable well supported platform for Linux
It's really not. A lot of software works, but when it doesn't, the user is SOL. As you can see on their Broken Software page[2], the major issue is precisely with AArch64 support. This should improve eventually, and Asahi is certainly a torchbearer in this scenario, but today it's yet another hurdle of using Apple hardware.
[1]: https://asahilinux.org/about/#is-this-a-linux-distribution
[2]: https://github.com/AsahiLinux/docs/wiki/Broken-Software