I am also an NIU alum and it's great to see their success. The Orange Bowl is a big deal! I really hope they can compete with FSU. The reality is, though, that they haven't beaten any good teams...their one loss was to an Iowa team that was terrible this year.
However, NIU is clearly just a feeder school. As others have mentioned, the money is much better at other schools...why would you stay for $400k when you can make $1M+ elsewhere? While I agree it's a little crappy to not even stay to coach the bowl game, I definitely agree with his decision to accept a huge promotion. It's the same thing the previous coach, Jerry Kill, did...both in coming to NIU from SIU, as well as going to Minnesota afterwards. We do it to smaller schools just as the bigger guys do it to us. It's all a food chain.