The FAA demonstrably is not interested in requiring minimum space and sizing on aircraft nor in re-evaluating safety of proper evacuation in the event of an emergency. Airlines are allowed to get away with paper exercises showing they can 'evacuate' pax, even though more seats are added and spacing between seats has dropped from when the original live studies and qualifications were done. If you actually try to evacuate a plane like a 739 now full of representative pax (normal mix of travelers, not experts coached in how to get off the plane quickly) then they will miserably fail the requirement to exit in the allotted amount of time.