For some odd reason the NFL stuck at 53 man rosters and NFLPA is okay with it. I agree with your sentiment but until the NFLPA stance changes this we'll just see what have been seeing for awhile.
Most QBs have some form of trade value, I mean Nate Peterman has a NFL job. So some team might like Fromm's potential and give us some low round pick for him if worried can't get him on the waiver wire.