Snead and McVay learned the hard way that it is fool's gold to give even a top flight RB a big 2nd contract. They get used up too quick and the team is left holding the bag.
If the evolution to the running QB is real, then how one chooses a QB in the draft, and how that position is handled long term, also changes.
My son and I were talking about this and agreed that what you try for is to select your running QB late in the 1st round (even if he might be graded a 2nd round type). You use him the way Baltimore uses Jackson.... he is part of their running attack. But, and this is the thing, every 4 years you do it all over again. No matter how good your running QB is, don't give him the 2nd contract and instead have the next running QB ready after a year on the team. You sort of put him in the RB category. So, yes, QB becomes a revolving door.
The philosophy is that while running QBs create havoc for D's, they simply don't last. So, acknowledge that and have the best of both new worlds. You never wind up paying a QB the big bucks unless you are foolish enough to pick up this type of player as a FA for a second contract.