You know there is a big difference between an offense being able to score from the red zone, let alone from inside the 5, and being able to move the ball from farther out. Beside, they wouldn't necessarily have had to score a TD to win. A FG could have been enough. The offense wouldn't necessarily have had to do much, maybe even nothing. Another interception, a fumble recovery, a kick or punt return could have put them in position for a winning FG even if it didn't outright score itself. A defensive stand leading to a punt followed by a first down or two and a FG could have won the game.
There is absolutely no reason to jump to the conclusion that the game was unwinnable in OT just because there wasn't confidence in the offense for a two point attempt.