In reply to Lots of people.
Sorry i should have made my position clearer, i doubt anyone who's not already climbed 7a/8a by the time they're 60 ever will, nor will anyone who's been dead already for a hundred years or people who never try climbing or don't want to put the effort in.
I think most people starting at an early enough age (when that is will depend on the person, I'm certainly not saying there isn't variation between people) who is motivated and goes about it the right way will be able to climb up to and maybe beyond 8a.
Different people have different strengths, but there's lots of different styles of route to go with that, raindogs at malham is pretty famous for having no section of climbing any harder than V4, and it's not even long.
Peoples susceptibility to injury is certainly variable but I believe very few people are so injury prone that without proper management it would definitely stop them. I myself have had many more finger injuries than fingers over the years, a torn bicep, dislocated shoulder from locking too deep in an awkward position and levering it out and elbow tendonitis in both elbows, as well as various pulled muscles too numerous to list. I have more than one friend who through bad luck managed to remove a finger and have climbed a lot harder than 8a without the usual complement. I know someone who managed to rupture his bicep, elected not to have it reattached on the advice that if he kept climbing it would just happen again and has since bouldered 8A+ without it (around 8b/+ in sport money).
I agree that anyone who doesn't want to climb any given grade enough to do the work required, whatever this may be, won't be able to do it but this can apply anywhere and i think broadening the definition of unable to this degree turns the debate into even more of a farce than it is already, anyone who doesn't want to climb 8a isn't worth considering when asking who could and couldn't.
Finally what does hard work look like, well i certainly wouldn't say I'm the most motivated, I've not yet been bothered to structure my training properly so I'm still nowhere near some of the regimes described above, but as so far i see reasonable progress with what i do that's fine.
What i am very very good at however is sieging the absolute s*** out of something, and this is where most of my gains have come from. If that's not for you then fine but it doesn't mean you wouldn't see the results if you tried. I'd just climbed my first 2 V8 boulder problems (hardly solid at the grade) when i had a summer ahead of me with very little to do, so i decided to try a long term project. I picked Lou Ferrino in Parisellas cave because handily I couldn't do a single move so it seemed long term enough. I went there on a bus by myself for 3 or 4 or 5, 2 to 4 hour sessions a week and it took me about a month to have all the moves down and linking 2 or 3 moves (out of 14) together at a time. Another month later and i had it in 2 halves, then started to push the lower half up towards the top. Probably luckily as i was starting to get some warning feelings from my inner elbows it subsequently rained heavily for weeks and the cave seeped and everything was unclimbable. This lead to 2 months of enforced layoff from that problem but a good chance to consolidate those strength gains elsewhere. When the cave dried out again it took me another month to push all the way to the top and do the problem, falling off 1 move before the end 3 or 4 times a session for about 3 weeks.
It was totally worth it.
Fundamentally I never feel like something's really been an achievement unless I've failed a decent amount at it first, the longer it takes the greater the achievement grade regardless (the edge problem which is V5 happened a long time after Lou Ferrino and felt like quite a big deal to me). I've climbed a couple more V10s now (though much more quickly) and my best bouldering flash is still a relatively meager V6, for those of you who've not done much redpointing it makes an enourmous difference.
I still think a lot of the "only special people can climb 8a" brigade have a massively over inflated view of how hard it actually is, and massively under-appreciate what redpointing really hard can achieve. The variation in age (16 up 40s who I've met, much broader that I've heard of) body type (girl/boy, short/tall, muscly/skinny as all hell/quite podgy) and personalities I know who climb that hard or harder is huge.
In summary to my essay, not wanting to doesn't count, and most people who might like to but don't either don't want it enough to do what it will require of them or have been surrounded by too negative an attitude from their formative climbing years to ever believe they could.
Post edited at 20:40