My take honestly is that this isn't the full explanation of what happened last year, but regardless you're not wrong, either. But I believe that Frost came in not quite understanding just how physical the conference would be. By the end of the Iowa game, he explicitly verbalized how out-physical'd we were and his offseason comments reflect this as well.
I think this is a product of prioritizing areas of improvement more than anything.
Either way: We're going to be in a good position to be much more physical this season and that will add to the win column for sure.