In amongst all the thread posted on Katir over the ages, this was my favorite quantifiable surrounding him.
These are the fastest 12 athletes in history (all the sub 3.29.0 guys), their first sub 3.30, their previous seasons best before that first sub 3.30 and the performance drop in seconds that they were able to manage at this threshold of performance
El G: 3.29.59 > 3.31.16 >> 1.57s
Lagat: 3.28.51 > 3.30.56 >> 2.05s
Jakob: 3.28.68 > 3.30.16 >> 1.48s
Morceli 3.28.86 > 3.31.00 >> 2.14s
Kiplagat 3.29.27 > 3.39.1(h) >> 9.83s
Ngeny 3.28.84 > 3.30.34 >> 1.50s
Cheruiyot 3.29.10 > 3.31.34 >> 2.24s
Makhloufi 3.28.75 > 3.30.40 >> 1.65s
Katir 3.28.76 > 3.36.59 >> 7.83s
Iguider 3.29.83 > 3.31.47 >> 1.64s
Cacho 3.28.95 > 3.32.01 >> 3.06s
Baala 3.28.98 > 3.31.97 >> 2.99s
Obviously the point of this list is to show that making the jump into the sub 3.30 club - even for the fastest runners to ever toe the line in this event, is rarely a dramatic one. We are basically looking at a 1.5-3.0 second improvement (averaging out around 2.0 seconds) but that's of course only if we omit two massive outliers in Silas Kiplagat and Mohammed Katir who made their ascension into the 3.2X's more akin to a high school kid going from the mid 3.50's to high 3.40's after actually bothering to put in their first good winter of training.
So how could Kiplagat and Katir do something so dramatic that none of their peers could. Were they just so much talented and what reasons could there possibly be? At least with Kiplagat his 3.39.1 is run in some tiny random town (Kakamega) just southwest of Eldoret at 5000ft which equates to a 3.34.0 sea level time. Not only that, it was run in his first year of recorded performances so this lack of performance history helps the plausibility in that it is possible he was just a massively untapped talent. Sadly for Katir he doesn't have this. His talent was tapped into - in 2018 he ran 4 races best time 3.40.84. In 2019 he ran 6 races best time of 3.37.61 and in 2020 5 races best time of 3.36.59.
What do I really think is the answer? Probably the same thing - especially now that the entire bubble in Kenya seems to have burst. But at least with Kiplagat there is no evidence of any sort of plateau/level finding. We simply can't say the same with Katir who never bothered with anything below 3.36 in the season before running not just under 3.30, but 3.29. Even Fermin Cacho who has the next biggest jump on this list at 3.06s (which is well less than half of Katir's improvement) had run 3.32.01 prior (also the slowest previous seasons performance of anyone on this list other than Kip), including running in the 32's 4/6 seasons prior to his (then) euro record of 3.28.95. I'm also not even taking into account that others on this list weren't doing stuff they shouldn't have because there is no chance all of these guys except katir were clean (point being even if bending the rules they couldn't manage such huge performance drops).
Bottom line, Katirs rise to prominence - in the 1500m event alone, was and is just not plausible and never was and none of this is sadly a shock.