15 limit is for guys that "might" get to play. Can still have "walk-ons" over 15, but if they're not listed among the 15 at the start of the season they can never play in a game
Done all he could do? Coaching isn't a one season thing. Doing "it" means doing it year in and year out. Doing it in one place doesn't mean you will do it in another. We seemingly determine success as the last 2-3 years only
Riley only had a handful of games where he got to 20 minutes, until the tournament. His last four games have been over 30 minutes each, all 40 in the championship.