The routes that he free soloes are also considered relatively easy to intermediate in skill level, well within his skill level.
The really incredible part of his free soloes is just how long his body can last. It's Olympic levels of endurance.
Even fewer will get to a point where they might conceivably flash or onsight 5.12d (<0.5% of climbers if I had to guess)
I doubt there are more than 10,000 people alive who would consider free soloing 5.12d at all, and I don't think anyone else has free soloed a 5.12d big wall route.
Style matters too. Are you good at steep overhung routes, slabby vertical routes that require lots of balance, crack climbing, or even off widths. It is all kinda relative. I am a tall guy so powerful long moves are my preferred style. I have friends a foot shorter than me that can crack climb way better than I can. It is a great sport and there are accomplishments to be made at every grade and every step of your climbing journey. Try hard and people with respect you regardless of the grade.
Physically the feat is comparable to running an ultra marathon, but to maintain the necessary mental focus for the entire push is beyond my comprehension.
“Requires considerable knowledge of ropework, knots, and protection to climb. Although "free-soloing", or climbing without a rope, is admired and even revered by some as the purest form of climbing, it is a rare sort of person that enjoys climbing significant class 5 pitches without a rope.”
Class 5 is subdivided in 5.1 through 5.15, with ¿some/each? having a further a through d rating.
The route he took is rated 5.12d, maybe 5.13a (https://news.ycombinator.com/item?id=14500208), so that’s highly elite. Free-soloing is easier than soling with safety ropes in the sense that you won’t have to haul up gear :-) but of course a lot harder mentally.
I think ratings ignore length of the climb, and that matters, especially in this case, where there’s little to no time to rest.
You have to be confident that you’ll be physically and mentally fit enough for the entire thing (climbing down is more difficult, so you’re committing going all the way fairly soon). For Honnold, that meant almost four hours.
For a dedicated sport climber the route would be very difficult but doable.
This is the route: https://www.mountainproject.com/route/106261545/freerider
30 pitches at 5.13a.
That is very very difficult.
Keep in mind:
1. Very few climbers can even climb one pitch of 5.13 (maybe top 1%)
2. Even fewer could attempt 30 pitches of 5.13 over several days.
3. Like maybe only dozens in the world could attempt 30 pitches of 5.13 in single day
4. Only 1 person ever in history that has attempted that without a rope.
See the topo here: https://m.huberbuam.de/files/hb/content/topos/HB-Topo-Yosemi...
(Not to diminish the athletic achievement at all. As you say, sending even a single pitch of 5.13a puts you in the top tier of amateur climbers.)