I think there is a place for trash and it's in the FA bag if they'd hit the aisles almost immediately after serving the "pig pax". I realize the system keeps pax in their seats, captive as it were and there is NO PLACE for garbagio--except at the seat.
We just flew too many legs to count this last week--and it's the same on all airlines--make us sit until we can't wait any longer---then a wild rush for the lavs creates another problem--what to do with the tray and trash?? Stuff it??!!
Logic and common sense/sensitivity on all levels would help, but they can be rare commodities...
There is NO excuse for bad manners anywhere--my husband and I always clean our room before check-out--a flight seat should be NO different. So sad...