And why exactly should it do that? Os development did not stop 25 years ago. AmigaOs is illl-designed for modern requirements. I always call it a "toy operating system" because it lacks any services that would be important today. Even if - the market works today different than it did 25 years ago.
Back then, computers were used by hobbyitsts, hackers, gamers, freaks... today, they are a commodity. You cannot expect a "modern user" to know what a .info file is, or how to "lay out" icons. It's all the wrong concept.
I know, but somewhere behind my head I have this sentiment that AmigaOS could takeover whole world

. I feel like 25 years ago when you actually could get Amiga500 in the store. It is somehow hard for me to think about AmigaOS as a pure "hobby" (even if it is for me... hobby!).
I actually did real work on my beloved A600 back in time.
Yeah, right. And this "worry about the pesky details later" approach was exactly the reason why the PPC experiment is right now where it is. "PPC is the future, let's worry about the applications later".
Really? From my perspective I did not see it, maybe from dev. perspective PPC was the future. I liked more AmigaOS, not necessarily as a best OS, but it was nice and CHEAP alternative to PC.
You need to understand that *today* the market works differently. Nobody worries about the hardware anymore. You have it anyhow. The apps are what matters. Commodity for the user. You don't buy a computer today because it is "cool hardware". You buy it because "it looks nice" and "it runs the stuff I need". It is reduced to things the average user understands: "How thin is it" (that is currently what people seem to want) and "does it do what I need".
Exactly, nobody cares about HW, but there is boatload of PC hardware and it will not go away "tommorow", and asking to pay $2000 for HW that can run AmigaOS in a relatively well is a LOT of money AND based on number of various motherboard revisions for AmigaOS4.x idea of having proprietary HW to run AmigaOS4.1 is simply BAD. Now, we have like few versions of AmigaOS4.1 for each HW? Strange.
OK. If not PC, why not to make it run on old MacPPC hardware. This "old" HW is way better then NEW and I can get PowerMAC G5 as a scrap metal price. Wait. I have old completely unused iBookG4 in my storage. That move would not require 100% "rewrite" of AmigaOS. Is that right? So why not?
AmigaOs cannot do that. The Amiga story as a "useful computer" ended last century already - as I say, this ship sailed away a long time ago.
This is a statement, that depend on attitude of person saying it

. Let say idea of "useful computer" based on AmigaOS is gone.
Why can't I install AmigaOS on MacPPC? You just wrote that nobody cares about hardware they use. Apparently people who own rights for AmigaOS care about $2000 mobos that is slower(?) then PowerMAC G5 and promise hardware for months or years.
It is taking about 2 years to release A1222. How long it will take to adapt AmigaOS for MacMini, PowerMac etc. It is funny how MorphOS "jumped" on new AmigaOS hardware and somehow MorphOS dev. could adapt it FROM Mac to new HW, quite fast.
Linux on PowerMAC, simply great speed:
https://www.youtube.com/watch?v=so35SrThHUs