Das been playing well, but Romo does make them a better football team because of his deep knowledge of the offense, as well as the defenses that he's playing against.
Dak is managing the game and playing very well for a rookie, but he doesn't have an incredibly in-depth knowledge of the entire playbook and offensive philosophy.. something that veterans build up over years, or even entire careers in an offense.. its the subtleties and knowing where every piece is suppose to be on every play without having to spend really any time thinking about what play you're running, or what personnel, etc... its just subconscious at that point and all the QB is doing is reading the defense and positioning his chess pieces to take them out
When it gets late into the season and it turns into playoff type games, that's when defenses start getting exotic and have film of every game their opponent has played to that point. Dak isn't going to be able to overcome all the crazy stuff that will be thrown at him that he's never seen before.. The older veterans have seen just about everything at this point, and that makes a huge difference from snap to pass
Not knocking Dak, he's playing very well for a rookie, no turnovers is unbelievable.. but sorry, the defense is also playing exceptionally and Dak is getting away with stuff because no one has had any film on him.. its just like if you have a regular group of people you play poker with once a month, then suddenly a new fish comes to the game and you don't really have a good read on them or understand their tendencies, so they can be more difficult to play against... at least at first..
They will need Tony Romo when its late in the season and they're on the road against a divisional opponent and need to execute a very complex/strategic gameplan