The team ahead can run the full 30 seconds. The team behind is going to average 10 seconds to get a shot off. Even if we give them a generous 50% make rate on their 3's, that's 80 seconds for every made 3. With only 240 seconds left, that's a grand total of 9 pts, 1 shy of the comeback. And that's assuming no made buckets at all by the team ahead.
I don't think anybody wants that, either.