I don't know why they would get into college hoops to take THAT job... its just not very desirable anymore... ridiculous fan expectations and a lot less local area talent these days
To your point, those 2 coaches can be very selective if/when they decide to return to coaching college basketball. That being said, I can think of at least 1,850,000 reasons per year, probably a lot more for either of those individuals. Coaches want to coach if they're still able to do so. It's their mindset. That's why Urban Meyer is returning to the sidelines. He had 2 relatively stress-free, decent paying jobs (Fox CFB analyst, Assistant AD at OSU) but still opted to return to coaching football. Beilein and Matta have come so close to winning a national championship; it's the one professional achievement their resume is lacking. I think that will weigh heavily on their decision (if offered) -- can they win a NC at that school? History says yes at IU, which has won 5 NCs in men's basketball, though none since 1987. Box checked.
There is plenty of really good basketball talent within @500 miles of IU's campus. Butler managed to make back-to-back appearances in the NCAA Championship game and it's located only an hour away from Bloomington. I don't closely follow IU sports, but my understanding is recruiting was not the issue for the Hoosiers under Miller. The players & system just didn't work out for whatever reason(s). A really good coach is not going to shy away from high expectations; they'll just make sure their contract affords sufficient protection, and that they can trust the AD to have their back. In the end, I really don't mind Indiana being down in basketball, as it helps Illinois and Ohio State in recruiting.