Signing a vet would ba step backwards. You end up overpaying for another team's disposable quarterback
You treat the QB position like any other, you constantly look for the best talent you can find while providing a competitive environment that increases the motivation to work hard and get better. No NFL player should feel completely secure with their starting status.
How many fans would have predicted that Cousins would Outlast RG3 when they were both drafted by the Commanders that one year. You just never know. However, if you don't draft QB's on a regular basis
Perhaps Mike White makes an incredible leap next season and It's possible the Cowboys draft a QB in the 2end round that turns into the next Drew Breea or Bret Favre, both 2nd round picks.Then there is still the possibility that Dak finds his comfort zone.
In any case, there's no sense in giving 10 mil to a second tier QB or a 12 year starter holding on too long. The problem with the Cowboy's is that they never invested much in developing QB's through the draft. One of the great things about the Cowboys in the 70's was that they always provided competition at that position even when they had a Hall of Famer.
Roger Staubach once admitted that one of the reasons he worked so hard was from looking over his shoulders and seeing guys like Danny White, Jim Zorn and Steve Deberg.