The difference is that today it is still the P5. When the P5 becomes the P2 not only will the resources ($) change but the desire of the Head Coaches, Coaching Staffs, S&C Staffs, Players and Recruits to compete at the highest level which will cause a re-distribution of talent between the haves (Iowa) and the have not’s (isu). I can see this eventually being a situation like the FCS trying to compete with the FBS today. Sure the FCS schools make headlines when they beat a FBS school today but that is because it is a massive upset. Same will occur over time when those not in the P2 defeat the schools in the P2.
Will isu football exist in 10-15 years, sure it will. Will they be playing at the highest level of College Football as they do today? I doubt it.