Seems that the "development" QB role in today's NFL is the one on the PS.
The #2 (on teams with a true #1) is cheap vet. I agree there is little reason to spend big $$ on back up QB unless you either have doubt in your QB (Rams dont) or have injury concerns (again Rams dont)
And while I agree the season is pretty much lost if the #1 goes down, you still need a QB that is capable of running an NFL offense. A late round draft pick cant automatically take that #2 spot. Either you carry 3 QB (No thanks) or you get the kid on PS