19 wins could also mean that that one or more players on the Celtics suffer season-ending injuries, and that we wind up shutting down our contributors for a majority of the season.
Not quite as dismal, but the 2011-'12 Warriors (featuring David Lee as their minutes leader, natch) wound up going 23-43 -- which you can roughly equate to 28 wins in an 82 game season -- after/during which/because they shut Curry down + traded Ellis for a non-functioning Bogut to protect their draft pick. They then went 47, 51, and 67 games, as well as winning a championship, as you might have noticed.
Of course they already had one player with franchise potential on the roster at that point, but he was a dude with bad ankles who was a distinct possibility of an overpay.