I can’t really speak to Fuchsia systems, but a lot (most?) Linux desktop distros use stub or systemd-boot bootloading these days. And if you want to get fancy, there’s rEFInd.
Which ones are you thinking of? Most 'desktop' distros I've used recently still default to Grub (Debian, Fedora, Linux Mint, Ubuntu) though I'd certainly be glad if change is on the horizon.
Course I'm a few years out of date
Also why MS' bootmgr stuff is still a flaming pile of junk.
Edit: And why MS has never given us a way to dictate where it installs its junk and/or to not install its junk!!!!!!
This means you can just partition everything from Linux and then install windows safely into where you select.
To clarify a bit too, as it seems it may not have been clear: grub was never run or installed inside a fuchsia system, I was building disk images from Linux hosts.
If I had to do it again, I'd probably just write a loader myself. It took about the same amount of time to fight grub as it would have done to smush together a basic GPT / FAT / jump chain.
The "install" scripts and so on are all horribly broken, and extremely badly behaved in terms of grabbing arbitrary stuff from the environment that has nothing to do with your desired target system. Using them for anything other than modifying the current host system is extremely sketchy at best.
I ended up re-implementing the whole process in a pile of bash (it should have been in something else, but I started in bash, and finished there). The slicing up of the bios segment that it does is also unnecessarily fiddly considering how it's all constructed, it would have been far easier to keep those segments in separate files and then you could just write one buffer after another in any language/tool environment you want.
The whole thing seems like an accident of history that no one wants to fix, which would be approximately congruent with all of the tooling in that area of the boot path, partition tools and so on.