Tbf majority demographics of YouTube are like:

1. Half probably bot net inflating viewers, astro turfing or annoying content creators

2. children who don’t care for HD cus they don’t know how to press buttons on their iPhone or TV, or mindlessly auto-playing watching kid shows or some dumb content creators

3. Everyone else, fifth or quarter of “everyone else” are probably vision impaired or old people where hd may not matter.

Also music vid viewers who don’t give a shit about video quality replaying over and over.

HD demographics are gonna be the minority when, need good internet (or patience), and don’t fall into above categories.

Personally I prefer HD vids but no way I can tolerate video buffering and shit ads on trash connection