I could be wrong, but IMO Smothers was recruited for an offensive system that Frost was already trying to move away from with the recruitments of Haarberg and Torres (taller, not as fast QB's). Frost wanted to have a QB who could run and got enamored with the speed and athleticism of McCaffrey and Smothers. After 2-3 years of seeing his QB's get beat up and not be effective enough passers, Frost began to look at bigger QB's who could stay in the pocket more. While Thompson and Purdy aren't big, tall QB's, they do seem to be better pocket passers than Smothers.