Redshirting QBs was very common up until fairly recently (last 15-20 years), but teams are also looking for ROI because these first round QBs cost a lot of salary now in year one. Pre free agency, you drafted a guy and had career rights, often at a low salary, so why rush him in? Also, in today’s game there’s a clearer path for guys coming out of college to transition to starter in year 1…a more organized process.
I don’t know if there’s that much benefit to redshirting, provided a coach is comfortable with the QB’s confidence and development (BB obviously should be), but my larger point has always been that the “second year QB leap” is largely a myth, so once a quarterback is put onto the field, he pretty much is what he is. Sure, he’ll improve, but the vast majority of the time we’re talking about a +5 passer rating gain and not a +25 gain. The idea of tossing a QB to the wolves because he’ll learn from mistakes and come back stronger seems to run counter to overwhelming evidence.