Not so sure about that. DEN's built to compete right now. For a relatively low #2, they can get 2 years of top QB play out of Romo and develop Lynch in the background. The same exact thing they did with Osweiler which, on the surface might seem like a mistake, but in retrospect you'd have to think they were pretty happy to do.
There's no way Tony'd re-do his deal to go to the Jets or 49ers right now. If he goes anywhere, it's to a contender. Otherwise, he just holds out, we release him, and he can pick his spot that way. DEN, MIN, LA, MIA...there are better options out there for him if he wants to make a run.
Or, he can sit tight in Dallas as a backup, redo his deal a bit and make it a lot more incentive rich, raise his kids, baby his back, and ride the snake to the postseason if anything ever happens to Dak. Who knows? I'd think he wants to play while he can, but with his injury history, it has to be for a contender who needs a veteran QB. Failing that, a backup gig where he is and where he has a home and likes the team is not the worst practical option for him, honestly.