They only run out of overhead room because dickbags put a carry-on and their personal item in the bin. Your personal item goes under the seat.

The other consideration it has is on net luggage weight. Yeah, they're still checking bags for "free" but they're smaller and lighter - saving fuel by increasing efficiency. And that's also a good thing from a pollution point!

Vote with your wallet (wherever possible)

The last large airline to NOT charge for checked bags in the USA, Southwest airlines, has switched to charging for bags.

Oddly the ones that have the best outcome for the deplaning scenario from this bad situation of paid checked bags are the ones that also charge for carry ons like Spirit or Frontier in the USA. So there is an incentive to NOT bring a carry on because you'll be charged for it and instead just pay to check a bag (which has more capacity).