The NYC commutability thing has been addressed before. The most recent I remember had to do with non NYC pilots flying international trips. In other words “why is ATL flying JFK-XYZ?” CR presented a lot of data about commuters including the distance of their commute and how that affects the operation when there is weather etc.

Along those same lines and I honesty don’t remember if it was in print or the dude from scheduling who used to come down to the lounge for briefings, but the gist was that they did not want pilots trying to commute in to NYC for late morning departures. (At least a in large numbers)

Of course that doesn’t explain the trips that aren’t commutable on either end..