[crabbone]

The complexity of GRUB isn't justified by the number of systems it has to support. The number of supported systems is also not the reason why GRUB is so complex. The cause of complexity is poor design choices, if you can even call it that, when it comes to configuration and defaults.

It doesn't matter that better options exist. GRUB is the subject of this discussion. If it were about systemd-boot, then it would've been legitimate to complain about it or to praise it. But, it's not the subject.

But, since you mentioned "other options"... they are both the indication of the larger problem: Linux boot process is poorly designed and that's why many independent teams tried to replace it to variable degree of success. GRUB isn't the only poorly designed piece of this process. And they work to obscure and make even less accessible the subject of system booting for the wider audience, creating a feedback loop where the only few people brave enough to dive in and try to understand it are the people who started way back and usually have very distorted ideas about how their code is used by the layers built on top of it.

The whole of the booting process didn't need to be this complex: it could have fewer stages, fewer utilities that are responsible for different stages, fewer possible boot scenarios, better defined order of device initialization... the list goes on. GRUB is only a part of the larger problem, albeit it's a big part.