I think the problem might be generational… the only people who know - or care - about the HIG are older millennials

Yes, the newer generation is used to computers being an inconsistent mess and slow. Only the the technically interested people know that it doesn't need to be this way. (And thus don't feed up with this and use Linux or *BSD :-) ).

yearning for old apple and order, current times and genz are more chaotic. not sure if it's generational, old apple was obsessed about design, now HIG is mostly optional. they now even use hamburger on websites which was a big no in the past.

HIGs change. what made sense for people who first used computers in their 30s might not make sense for people which used them since 7