From a public health perspective Delta might be enough to F-up our stuff and lock down again. It kind of depends on the effect on kids and hospitalization rates for vaccinated. If you have 30% unvax + some amount of break through * 10x infection rate than you are going to have problem pretty quick. Especially if indoor transmission is as bad as it seems to be, even regular pressure from flu+covid break through is going bring the medical system into chaos mode again.
Chronic healthcare under capacity is going to show up with a vengeance again this year even if we had 100% effective vaccines the anti vaxers would be tying up all the normal resources. The health care system struggles on a bad flu year so unless we miss flu season again this year were going to be really f-ed. Mask mandates will have to come back (if nothing else to hold the flu at bay) and free up resources for dealing with break throughs and anti-vaxers. Maybe mask mandates dont snowball into lockdowns, maybe they dont but winter 2021 is going to be rough even in our part of the country (anti vax land is either going to vaccinate or they are going to going to have a really bad time).
Public health officials are going to have some difficult choices to make - i think inevitably they will have to shutdown because dispite the vaccinated folks being safe enough, the unvaxed will eat up so much hospital resources that insufficient capacity to do routine ER stuff will start to kill folks but perhaps not. Maybe we just accept that we do not have a functional/available medical system as that's already the reality for many Americans. Im sure a bunch of public sector employees will want another 6 months paid vacation so there is that too.