I agree with parts of what you're all saying (grimer, JB, Paz). The reasons I think that there aren't many people onsighting E7 and upward on grit are partly that the routes are quite hard, partly that even if they're not that hard they're easy to fluff and partly that there aren't that many capable people interested in pushing the standard forward.
Grimer - no offence taken at all. I didn't do anything remotely hard on grit partly because I didn't reckon I was that good on it, partly because yeah the routes are tough to onsight but mainly because I wasn't really interested.
You have to remember this was before the headpointing 'explosion' and nobody I was climbing with was interested in climbing hard grit. People like Malcolm, Smythe, Cupboard, Gaskins and even Gresham back then were all just into training, bouldering and going to Buoux. Gritstone was nice for a day out bouldering and soloing easy stuff but the cut off was E4/E5 for me because anything harder would have taken proper commitment instead of being fun.
Perhaps if I'd not stopped when I did I would have done more but I doubt it as top roping stuff and then leading it never really appealed to me. Onsighting was always what I enjoyed on grit but the level of commitment you're talking about with most E7s was certainly not. I think I got scaring myself out of my system by the time I was 14.