The issue right now is the governement have high hopes on a vaccine. And yes if it work at 60ish % like other vaccines, then thats 60% less chances to catch it and the spread would slow naturally. BUT who knows if or when it will work.
I think peoples just need to be smart at the moment.
If you are "at risk" then be carefull
If you are close to someone that is, be carefull
If you work in a nursing home/hospital, be carefull
Thats just common sense. Its been obvious even before mask (and i maintain those are a placebo for whatever reason) that a visit a the grocery store WOULD NOT be the contamination factor. Unless you REALLY go after it, like see someone you know, go talk to them super close for a long period etc.
The contamination usually happen in bars, private parties, stuff like that, so as long as its young and healthy peoples who get it, its not that huge of a concern. I know there will be some exeption, there is in everything, sometimes you see a 20 y.o hockey player have a heart attack. Rare, not impossible. And its sad for them, but we can't stop living for a few exeptions, just like we won't slow down the speed limit to 40 km/h on the highway cause it would definately save lives. The peoples who die each year are sadly seen as "acceptable losses".
So yeah virus mute, immunity may not be permanent or even 1 year long, but if some peoples do get infected and develop it, for i dunno, 4 to 6 months thats a person less that may get it afterward and spread it. If the vaccine was SURE to be working at 80% and announce to be ready in December, like everybody i would say "fine, lets endure" but since it could be 2 years or even NEVER, we don't know, life must go on. Businesses can't go bankrup and peoples being in big trouble forever.
So... keep the curve "flattened" to an extent sure, don't overload hospitals, but at the same time don't go full lockdown full "we must stop living" because of this virus.