MacOS still ships x86 builds, and most software either provides binaries for both platforms or some kind of universal/hybrid binary. Still a few years before that becomes an issue.

At some point an ARM->x86 translation layer is going to be needed too, regardless. It's not long until ARM becomes popular enough to make it necessary to translate both ways.

Ubuntu was the “original” easy-to-use Linux desktop. It expanded into that demand and still enjoys the market share it got when nobody else was really filling that niche.

Mint exists explicitly as a fork of Ubuntu and enjoys less success as a result. Many, including me, think Mint does a better job at being a solid desktop option than Ubuntu and is kind of the goto distro for that now ( not still not as popular as Ubuntu still is ).

Elementary is a curated desktop for people that really like coherence and design. That is, first of all, a more demanding target. It is perhaps too ambitious for their scale. And they have stumbled in execution. The task might be easier if they focussed on just being a DE ( desktop environment ) that other distros could use.

An “official” Ubuntu or Mint spin would have a real shot.

Pop is the only one that really ever makes any reference to windows in its marketing. I'm more talking about distros like Zorin which are targeting public sector orgs and windows users by bundling windows compatibility apps and features into the ISO.

The other examples definitely do also target "new users" which of course means Windows users too, but they aren't explicitly tying their distros to Windows software compatibility the same way some are.

Pop is the only one that really ever makes any reference to windows in its marketing

First line of the the description of Zorin on zorin.com/os

“Zorin OS is the alternative to Windows”

zorin.com/os/

They are probably saying the shared POSIX underpinnings means greater commonality between macOS and Linux and therefore easier porting. That is likely true to some extent but real apps are written to Apple proprietary APIs and therefore that advantage is largely nullified.

In terms of effort to bring apps over, there has been far, far more effort put into porting Windows apps and so that task ( at this point ) is generally easier. It may have been less effort to port macOS at the start ( eg. GNUstep ) but that work has still largely never been done.

It is easy to move POSIX world apps to macOS. It is not as easy to go the other way.

I think (aka speculate) that the fact that Windows is the largest OS plays into the fact that Linux-Mac compatibility isn't more developed.

I bet some 90% of desktop software is available on Windows (even many core KDE are on Windows!) so targeting them brings most Apple apps onto Linux "for free". Especially since Apple's insistence on trying to make Metal a thing hurts gaming support, which is a big driver behind Linux compatibility development.

The few applications that MacOS has over both Linux and Windows are usually so embedded into the Apple ecosystem that you're not getting much by porting them anyway. iTunes? The App Store? Garage Band? Probably doesn't help that many of those apps also use Apple's own UI framework which isn't really portable.

However, stuff not designed to live in Apple land like Teams for Mac or Adobe CC might be more possible. But still far too few applications to necessitate the effort to bring them over.

Absolutely.

A lot of it is just the organization and leadership within the projects themselves. The GNUstep guys struggled for a long time. Just agreeing to implement the Mac APIs instead of just the NeXTstep ones is a thing.

Regardless of how attractive projects are, they can be run well or badly. Without trying to disparage anybody, look at the progress of WINE vs ReactOS for example. And if you think it is just because kernels are hard, look at Linux or Haiku or SerenityOS vs ReactOS instead.

But the popularity of Windows made the Win32 APIs more commercially viable as well and so you get companies like CodeWeavers and Valve that really accelerate the WINE effort. That wind at your back really helps.