There's one aspect that no one seems to be giving any thought to: the psychology of breaking the 1:42 barrier.
Wanyoni broke it! Once he did that - becoming the 1st this season to run 1:41, he set the bar - and showed that it was possible. Then 3-4 guys ran 1:41 in same race (they new it was now possible - and if you cant run that fast, you are not worthy); next thing you know Marco Arop runs 1:41.20 (a PB by 1.5 seconds); Hoppel runs 1:41.67 - a PB by a second, and a NR by 0.67). Then Crestan, PATTISON, run low 1:42s, and 2 other Kenyans run 1:42.08.
Back in the day - when Bannister first broke the 'impossible 4minute mile' - suddenly others came out of the woodwork and did it. Within 4 years it was 3:54.5. The 'psychological barrier was broken.
Back in July, when Arop's PB was 1.42.85 from 2023 (remember he was world champ that year) - he watched 6 runners run between 1:41.48-1:42.43. Imagine what must be going thru his mind.
Bottom line is ... he had to re-set in his mind to what was possible - and raise the bar of what he had to do - and he did it - running 1:41.20.
Was he fitter than he was in 2023? Of course, he must have been, BUT - the psychology of the mind has to account for some (a lot ?) of that improved times - not just for him but for Hoppel and all the others.
Was better drugs a factor? I don't think so - otherwise, why did it impact ALL these runners in the same 2 months this year, but not other years? I don't buy it.
Also - look at the 400m hurdles. Check the top 8 times from each of the last 10 yrs - they were crap times 8-10 yrs ago (few sub 48s), then all of a sudden, these last 4-5 yrs there's 3 guys regularly running 46s.
Karsten broke the barrier, then De Santos + Raj accepted the challenge and upped their game.