So there’s good reason to believe it may be macOS only.
Personally I’ll believe it when I see it... because right now there are no 3rd party iPad or iPhone operating systems. So a better question is probably: what makes you think there will be 3rd party OS support?
https://news.ycombinator.com/item?id=24636166 (Apple’s T2 security chip jailbreak)
Yep, curious world.
Getting Windows to run on this is a pretty tall order, and without significant investment it won't happen. And significant investment from whom? Not Apple surely. I'm guessing Microsoft has more stake if anyone. At best we're going to see Windows on ARM virtual machines.
Speaking from what people expect from a "Windows PC" - Windows on a current MacBook makes a decent Windows PC. Windows on a future MacBook makes for a very poor Windows PC that will make customers regret their purchase.
Apple currently uses standard PC architecture, with identical CPUs, GPUs and Wifi chips to standard PCs, and a (sort of) standard EFI booting mechanism. With ARM Macs, it won't. Clearly Apple in its hardware design is already not invested enough to support Windows - they could use standard EFI on ARM, for example. So why would they spend a lot of money to do it in software, so people can run a "crippled" version of a competitor's OS?
Note I don't actually believe Apple will actively lock this down. I do believe we will get native Linux on these things to some extent. But I do believe Apple will not lift a single finger to make alternative OSes happen on ARM Macs. Apple only cares about macOS and virtualization. I also think Windows on ARM is a great product, but I also know that common people that just want to use a Windows computer won't agree with me.
The "Apple is going to lock down the Mac just like the iPhone" narrative has been with us since, well, the iPhone. But despite the alarm at tighter security measures in more recent versions of macOS, that hasn't happened yet -- and if a Secret Nefarious Lockdown Plan (tm) was going to come to fruition, the year that they shifted CPU hardware and radically redesigned the operating system's UX would sure as heck seem to be The Perfect Moment. And it still hasn't happened.
Past performance is not a guarantee of future returns and all that, but I don't think there's any reason to think Apple is going to make it any harder to run different operating systems on Apple Silicon hardware than they do on Intel hardware. (Of course, I don't think there's any reason to think they'll make it easier, either.)
But arm macs are really an Apple A series processor plus a number of coprocessors like the t2, nueral engine, etc.. and the default is that windows will not work on this specialized hardware.
So unless there’s evidence that Apple is actively going to help 3rd parties develop operating systems for the Mac, the best we can hope for is a fairly acceptable OS with reverse engineered drivers for those chips. We’re either going to get an unstable OS or a severely crippled OS.
With intel macs Apple just had to stand back and let 3rd parties do their work. But they would have to actively assist with arm macs.. and there’s no indication theyve ever done that much less intend to do so in the future.
And I don't think it's a coincidence Apple is slowly but surely moving OSX towards a locked down platform. It's already made pretty hard to run normal software.
“We’re not direct booting an alternate operating system,” says Craig Federighi, Apple’s senior vice president of software engineering.