Of all the complaints about rust, this strikes me as one of weirdest. How much code do you actually write for architectures outside the Tier 3 support list?
However I did write ADA and C for those.
Ok, but recently? I too wrote code for obscure platforms once upon a time, but not in, say, the last 15 years.
Now that PCs, game consoles, and mobile devices are basically all either amd64 or ARM, there's just not such a long tail of weird platforms to develop for.
(the embedded world I will grant you, still lots of bespoke toolchains running around in that space)