Domestically--there's not much excuse.

If I was being generous and understanding, I might allow for an Einstein excuse (i.e. time and space). On a 767, with a longer boarding period, two aisles and a galley with two routes of access, you can more effectively fawn on J pax than on an A320 with one aisle, one access route, and almost as many pax (24 as opposed to 36/35/25).

However, if I was being cynical (as is often my wont) I would chalk it up to parsimoniousness and a general decline in service.