It seems to be my understanding that Linux will allow supporting any hardware or software API as long as at least a few people care about it. It doesn't matter how old or impractical it is.
This is not a criticism, but I would like to deeply understand, what does Linux leadership want it to be? An OS that just runs on anything for the sake of it?
It already seems true that Linux aspires to be much more than what UNIX is. It can be a dumping ground of sorts for your ideas and research projects. As long as the code does something useful enough without corrupting the entire system, it seems to be fair game. That is kind of freeing and it would stand to benefit the project to be communicated more directly. These are my observations.
A counterexample would be that most other open source Unixes' "MVP-level" of hardware support meant that none of them gained much traction and market share. The real world does not run entirely on Thinkpads.
It happens again and again:
There's a plateau of Real Computers, where Real People do Real Work, because they wouldn't deign to deal with the oddities and lack of performance peasants put up with on their Bitty Boxes.
Then something nasty happens, and those Bitty Boxes become more capable without becoming correspondingly more expensive. All of a sudden, the companies selling Real Computers no longer have a value proposition: Their stuff may not be hugely more capable, but at least it's massively more expensive!
Eventually, not even the Real People can continue to ignore the fact the Toys are smoking them in every benchmarkable metric aside from cool factor.
It happened to DEC when minicomputers fell to PCs, and it happened to Sun and SGI when the "workstation" category got folded into the "somewhat-more-expensive-than-usual PC" category.
Linux originally ignored the extreme low-end PCs, but in 1991, it was pretty clear than 16-bit x86 CPUs were more trouble than they were worth in the Unix-like world and it wasn't a good move to mutilate the kernel to fit on a kind of system which was rapidly becoming obsolete. However, Linux is not ignoring the current Bitty Boxes, the SBCs which can run the kernel with no compromises once you navigate the weirdness of ARM-based hardware.
(Yes, there is a project to run Linux on 16-bit x86 chips and other MMU-less CPUs. It's called ELKS and it was never very active.)