You simply cannot compare Shrewsberry and Johnson. He was an assistant coach on teams that went to back-to-back national championship games and then was an NBA assistant for 6 seasons. He then was Matt Painter's lead assistant.Or, to say it another way, as much money as is available for a new basketball coach - which might not be as much as more than a few other places. Much has been said around here about the "equity or social justice" angle of this hiring but maybe some of that was just putting lipstick on a pig. Better to say that we're promoting equity in hiring instead of we're just cheap or broke.
Like I mentioned previously, Penn State never seemed to care that much about basketball and they hired a coach with negligibly more experience than Ben Johnson (he was associated with a better program as an assistant but a brief tenure as a head coach of a moribund NIAA program isn't much) for around the same amount of money. But, Shrewsberry surprised and I think PSU decided they liked that exposure from a run through the Big Ten tournament and an NCAA tournament appearance with a win. So, after he departed, they forked up the cash for a mature coach with a demonstrated track record of success. Will Minnesota do the same? Well, they didn't with the last two hires and the fatter TV contract may not matter.
As to your question about Coyle being cheap and maybe using equity as a way to hide cheapness. Maybe, except we were no where near as cheap as we had to be to get him. We probably could have paid him half of what he got. All of that said, that's not the ADs decision. They are essentially given a budget by their bosses of which to work. Every AD would like to spend as much money as possible, it makes their life easier.