Wow! I just don't know what to tell you. No team carries 3 or more vet QBs. You carry a starter, a vet backup and a developmental QB. If an injury happens, you adjust. That's what we did. You can't carry veterans three Deep at every position. There's this thing called a salary cap and a 53 man roster. You simply make adjustments when you have to. This is not hard to follow.
Yes, there is a salary cap. No, it doesn't prevent a team from having 3 veteran QBs. The cap charge difference between whatever experienced QB you would have compared to the "developmental QB" is inconsequential.
Yes, there are roster limits. Half the league has 3 QBs on their 53 man roster so apparently having 3 QBs is not impossible from a roster limit standpoint.
These are non-issues. Neither of these is why teams typically don't have 3 veteran QBs.
Furthermore, I know you'd like to think Dallas had a starter, a veteran backup, and a developmental player but you must not have been paying much attention to Coach Garrett over the last couple of offseasons. Brandon is the developmental player. He said it himself so it looks like Dallas actually went into the season with a starter and 2 developmental players. Seems like there might be room for a veteran in the mix, no?
The real reason most teams don't have 3 veteran QBs is because there aren't enough veteran QBs. Hell, over a dozen teams have a backup with 4 or fewer seasons in the NFL. Same as Kellen Moore. That said, a team who saw a need for 3 veteran QBs could most certainly make it happen. Say......a team with a QB with questionable health.......or, maybe a team that would feel the need to acquire another veteran QB if their starter went down. They could make that happen during free agency.
There's my dislike for the move. Dallas has a QB with questionable health, and they just felt the need to acquire another veteran. Not only does this highlight the fact that the cap and roster limit are irrelevant in terms of a team's ability to carry 3 veteran QBs, but it also raises the question as to why they didn't just sign Cassel (or someone else) during free agency. What if Cassel would have beaten out Weeden for the backup job? Would you not feel any more confident with the winner of the backup job starting this week compared to the developmental guy who was handed the job on a silver platter?
If you knew your backups weren't up to snuff and you knew that you would seek a better alternative if they were called upon, why the hell didn't you just seek better backups in the first place? What sense does it make to say, "we're confident in our backups provided they never have to sniff the field"?