I don't think many folks here are of the mind that things will go back to exactly the way they were pre-COVID. I certainly think that some things like mandatory hand-washing outside restaurants will stay in place, and maybe proof of vaccinations prior to boarding, too. And I also believe that Disney will set things up where more health protocols will be easier to "dial up" and "dial down" on a dime, as needed.
But, IMO, the cruising public simply does not want a segmented, regimented cruise vacation like this. Some will abide short-term while we are still in the thick of COVID-19, but once things simmer down, people will stop accepting (most of) these restrictions as acceptable compromises for the risk involved and the money being charged.
again, proof of vaccination is a short term thing.
we are not talking about the yellow fever, which you need the vaccine prior visiting Africa. Maybe some countries will ask it, but certainly not the US or Canada.
some measures will stay, such as handwashing before entering shops and restaurants maybe, temperature check before boarding ?