@Kronos
In my imaginary timeline i defined it as 20 to 30 years, so i dont expect x86 to vanish over night either. Most have also noticed that Intel especially is flooding the market ATM with affordable, cheap x86 SoC's. You can pick up an i5u with 8|16 gb ram and intel MESA for $50-$100 second hand (20 watt mobile version). I just bought 5 ThinkBox'es that i refurbish as gaming boxes for $180 with 1 year warranty, so x86 is not going down without a fight.

Single core is a problem, a complex one that touches on everything from memory management to process isolation and hypervisor modes, so yes, that wont be easy i imagine. One approach would be to thread the desktop itself, while running processes are limited to sharing a single core. Not optimal, but it would be interesting to see where that leads. I mean, node.js|deno somehow delivers acceptable performance as non-threaded runtimes, and it's async model have some synergies with Amiga's multitasking model (at least in principle, most likely not in technical terms).

The Rock PI 5 is probably the only "desktop level" Arm SoC that we have at the moment, bar Apple's M2|M3 architectures. Tests are en-par with an i5-2600, using more or less the same power (20-30 watts). I was quite impressed by it, it's miles ahead of Raspberry PI 4 (I have not done any benchmarks on PI5 yet, I am more a fan of ODroid N2+ and RockPi).

SnapDragon is coming with a new series now, made by the same people that did the M2 apple silicon. They quit apple and started their own company, and got bought up by Qualcomm. And unlike apple, their new Snapdragon will be a general purpose SoC, so there are "options" out there.

I write compilers and devtools for a living so I usually have an eye on these things, and i try to think 5-10 years into the future. And I really would like to port over my devtools to Morphos & OS4, but then I have to ask -- is it worth the 2-3 years of work to invest in the platform?

Like most things this boils down to money, accesibility (hardware etc), and demographic. While I applaud MorphOS and its developers for an amazing achievement, and I pay my license with joy, I cant help thinking that there is a lack of initiative in the NG camp lately.
I just forked out for an A1222+, just so I at least can work on that platform (and so I can say that I have supported NG through thick and thin), but I am perplexed at the lack of "vision for the future". I mean nothing negative about this, so please dont misunderstand me. I find it frustrating because I want MorphOS to succeed, grow and become the success it deserves.

As for emulation and supporting that, MorphOS could generate virtual hardware specs, hash the configurations, sign and crypt this to avoid tampering -- and offer a prefab download that includes qemu and said file-setup. QEmu is vanilla C/C++ so should not be difficult to mod it to use this special file-collection, much like Cloanto's RP9 system or vmware's virtual disks.
Heck, i would buy 5-6 licenses immediately and run these on my cheap i5 PC's so i can remote-desktop into them from my devcenter.

There are money to be made, but it requires some engagement.
I hope to see an AMD build or ARM build, I for one would welcome it wholeheartedly, and I know a lot more people that would also adopt it in a heartbeat.