I'll give the coach the benefit of the doubt. Seems like an impossible and unfair metric. You could claim that all player development at all places was just due to acclimatization rather than coaching.
If it hasn't been good over that time, then why didn't he get fired in 2023? 2024? Didn't he get promoted to Co-OC, in fact?
Just seems like a weird deal.
Either gut the staff, or give them one more year to figure it out. Makes it feel oddly personal, or something, to only axes one of the three main guys.
With how he has continually passed him over for promotion to the main OC, in spite of a great playcalling performance in the 2019 bowl game, maybe there is something to that ....