1) Starting QBs aren’t supposed to lose their job due to injury. They are supposed to be replaced by better play.
2) Romo suffered a freak injury, was medically cleared to play by the doctors, and was in his best health in the past five years. If he suffered another freak injury or played poorly, the team could always go back to Dak.
3) Romo was clearly the better QB in practice as Barry Church and others testified to.
4) Dak did not win a QB competition in camp nor in practice. It was not allowed by dumb and dumber due to 4.
5) No rookie QB had ever taken a team to the SB.
6) You don’t make football decisions based on chemistry, a hot hand (which are for sports like basketball in the game, not football between games), or the superstition of messing up a win streak, which ultimately always come to an end.
7) Dak fell into a talented team situation where it was never clear that the victories were due to his play at a superior QB level (and that Romo couldn’t do the same) as opposed to just driving the bus. In games against the Minnesota Vikings and the second Giants game, he was mediocre, if that.
Those are just some of the things I came up with off the top of my head. I’m sure others could come up with more.