The 800 is the most difficult race distance to pace correctly for maximum performance.
You run the sprints all out.
Even in the 400, you are barely holding back the first 200.
For 1500 and up, even pacing is most efficient, so you pick your goal pace and try to maintain it.
In the 800, you have a 1 to 3 second positive split difference from the first lap to the next. And every 200 is run slower than the preceding one.
That's true for probably every sub 1:43 ever.
Though, some runners are better with that 1 second difference while others are best with the 3 second difference. And each runner has to find which fits them best.
And you are running a fast pace in traffic. Any step that you chop or stride running wide hurts your overall time a lot.
I think a lot of 800 runners go their whole career without running their perfect race.
Look at all the runners that hit lifetime PRs in the 2012 London race.
Did Nick Symmonds have better 800m ability than Paul Ereng?
I also think runners specialize more now.
Besides Coe and Ovett, you had 1500, runners Cram and Peter Elliott than ran 1:42, mostly as a good speed workout for the 15.
Makhloufi put up a good time last year. Kiprop doesn't go for a fast 800 often.
El G and Lagat never tried to put up a good 1500 time.
That hurts the depth of fast potential 800 times.
I think the 800 talent has progressed even if the level of fasts times hasn't shown it.