To the OP, I think the fact that we pay top top dollar for coaches and assistants has a lot to do with it. Texas is a destination job like few others, so when coaches finally get here, there is a certain sense of "I've made it". I think what motivates a lot of younger coaches is to get to a place where they feel like professionally they are at the top of their field and Texas touches that box.
Once here, I really think they stop grinding like they did when they were younger and hungrier. They coast a bit. Throw in the huge amount of money we always pay and the coaches have realize a windfall if it doesnt work out. We do things the right way in terms of employment, its professional, coaches all get treated well and its not a grind anymore to them.
Take Auburn, Maryland (only b/c they beat us recently), OSU, Baylor etc...coaches jump ship from there all the time to take bigger better jobs. The replacements are always working their asses off to make it. Unless TX coaches get fired, they would never leave, so all they have to do just enough to keep their cushy job.
The only way to change the culture is to hire a stemwinder like Saban or Meyer. The people (I work with high net worth individuals) I work with that have the most $$ and run the most profitable/successful businesses have two things in common:
1. they have the best Leadership
2. they have a Plan
We have not had the best Leadership since right prior to Mack winning the title. After the title, the rot set in. Everyone was getting paid huge amounts of money, Strength guy, Coordinators etc...add in Mack trying to change the plan (to go more Bama heavy run oriented Offense, missing clear signs the HUNH was coming), compounded with the the lack of hungry assistants (brought on by big salaries and a title run) and a lack of plan to deal with complacency is the reason we have under-performed the last 15years, imo.