You assume Allen is a competent coach, just like you assume no one else in the division will get better. Health is nothing but luck and not a valid excuse for good coaches.
Allen won’t be less competent next year than he was this year when we were one game away from winning the division.
A better QB is worth at least one game. Barring one of the other three teams adding someone better than Carr (Jackson?), we would be instant heavy favorites to win the division. We already are the NFC South team with the best odds to win the NFC, and that’s without a QB.