Masks will be the last to go. "Herd Immunity" takes place when 95% of the population is vaccinated or has had the virus and has antibodies. Considering the child population isn't getting vaccinated yet this won't occur for some time. Also, you still have roughly 35% of the adult population saying they won't get vaccinated. Masks will be around for some time. I agree with OP that everything else might drop or reduce, including social distancing, but masks will be around. On the good news side, if the rate of vaccinations continues at the current pace, and the pharmaceuticals continue to deliver (including J&J), by Memorial Day 80% of the US adult population will be fully vaccinated. (If we can get them to take the shot!) The potential for things to be somewhat back to normal by Memorial Day is there.