The extra time also let them build more quality depth, but the issue with BYU, Utah and even TCU was never the 1s.  The 1s at all 3 schools were competitive with P5s already, and stayed that way.  It was getting better 2s and 3s. 

But Utah struggled more than TCU to transition for 1 simple rason--QB play.  And the years TCU has struggled has been due to QB poor play, not overall ability. Same with Utah.  When their QB play is subpar, they struggle more. When it is good or better they win more.

Seems to me the key to P5 success is QB play, and always will be.  Depth will certainly improve and will help, but QB play is the X-factor in the P5.