A very good retrospective, Mr. Beer.
However, I think the future for both KSU and ku lies somewhere in between the fate of both programs from 1990-2005. Neither coach is likely to be Bill Snyder, and neither coach is likely to be Terry Allen, honestly. If the premise is really true concerning coaches needing a critical number of years at a school to get "their" players, then the Big XII north should look like this:
MU > ku > NU > KSU = CU > ISU
Really, that's pretty close, though its eminently possible that NU should be equal to or slid beneath KSU and CU based on the results so far this year.
I think the interesting question going forward will be: who will truly be the next Bill Snyder of offense/defense in the north? That is, who will be a pioneer and do something that no one else in the division (or CFB) is really doing and get an edge? Snyder went to the 15-yard out as the base of his offense when the conference was still three yards, a pitch, and then a cloud of dust. Then, he was the innovator of the running QB/hybrid offense. Right now MU & ku have gone all Abercrombie and Fitch on the Big 12 north, running the vogue spread. KSU and NU (and CU to some extent) are currently pretty traditional with trying to be balanced (though they all rely on the pass more right now than they would like). ISU just turns it over.
Prince may be "bold & daring", but I would sure like to see a wrinkle in the KSU version of the WCO to make KSU just a little different. Tech uses the spread, but it's a ridiculous mutant version and it works. What will Prince (or Mangino, for that matter) do to make the offense unique and tougher to prepare for? That, I think, will determine what dictates the success of the football programs in the state of KS in the near future.