I think with social distancing, which the majority of the public agrees with, simply will not want to get into a crowded RJ or 737 where social distancing is impossible and air in the cabin is recirculated. I believe more spacious cabins are the future.(A32x, E175).
Right now is the best time to fly with cabins at 30% occupancy.
People will revolt and never fly again if you bring the loads back up to pre covid levels at this point in time.