If there was any doubt before, I think it's now confirmed that QB is the most important position on the team.
Therefore it would seem prudent to put extra resources into that position each year, such as drafting one in the mid to late rounds that could be groomed but make it to the the PS, and also sign an UDFA. Look at Ryan Leaf and Joey Harrington and all the other busts that have come and gone, and it's plain to see that it really is difficult to find a franchise guy. but that means it would be sensible to look under more rocks rather than less, and sooner rather than later.
I agree that using a first rounder on one is not going to guarantee immediate success (see Aikman, et al), but it may at least set the team for the future if said team loses their #1. Unfortunately, at best case, the first 2 or 3 seasons will probably not look too good unless the #2 is solid (and who has that?). And if he busts, there goes a few more years of futility (see Cleveland).
NFL talent evaluation is a risky business, no question about it. But it would seem sensible to constantly to have a steady stream of young candidates, from which a potential franchise guy may emerge, instead of relying on someone else's rejects.