According to ESPN, IU's strenth of schedule (SOS) is very similar to Notre Dame, Ole Miss, Michigan, USC. Their SOS is stronger than Ohio State, Texas Tech, Miami, Utah, Georgia Tech.
Old Dominion, one of those cupcakes as you call them, actually has a much better football power index currently than Northern Illinois had at the end of last year....the same team that took down the Irish.
There is no doubt that Notre Dame started off the year with 2 outstanding programs...but their SOS levels out during year as the quality of most of their opponents were "meh". That is why their overall SOS is very similar to IU.
I am not picking on Notre Dame...I have no problem with their schedule. I do get frustated when Finebaum and some others poke at IU's schedule, when their SOS is pretty much the same as the programs I mentioned above, that doesn't seem to get the same finger point. I think this is mainly because they are "the new kids on the block".