In reply to Roadrunner6: You'll find there's a lot of people you think have run sub 30,, but then it's only a low 30. Consistent, repeat sub 30'ers, not so many, ditto <65 1/2m, sub 49 10miles...
But there have obviously always been very strong mountain, fell runners of course. Back in my day Paul Dugdale, Marting Jones. Very often 'jack of all trades' like Paul D, bit of track, xcountry, some fell... Martin Jones was an oddity who really did burst onto the scene from the fells, initially making a big impact running road 5K's ..
The people doing ultras at the time really were not very fast.. 34 minutes 10k'ers getting in the UK team.
One observation i have from that Norwegian race is how deep it was in quality. When I moved here the standard was not so good apart from Marius Bakken, and there were only a few people 0 per year. They've made a real push to take what they knew from X.c ski and improve distance running, with obvious sucsess