It seems some people have trouble with some basic logical facts. Let’s go through this together.
If you do not come into contact someone with a contagious virus at all, you will definitely not catch it. That’s why nobody got COVID, say, last year, because there was nobody to catch it from.
If you do come into long, sustained, close contact with someone with a contagious virus there is a high likelihood of catching it, and your chances increase or decrease depending on many factors.
If everyone would stay locked down fully and completely the virus would be completely eradicated in short order. This is a no brainer. “Quarantine” always and forever works.
The questions only arise in implementation, when, how, how strict, what about people who must break the rules, what if it’s too late, what if it’ll take too long, how bad are the ramifications of the lockdown vs. the ramifications of the virus, what if it’s transmissible through other methods that are hard/impossible to prevent, etc. That’s where the debate is. Even in Sweden, the holy grail of no lockdown, anyone who wants to be cautious and not catch the virus is obviously trying to stay home as much as possible with as little contact with others as possible.
Again, these are all basic logical facts that any thinking person should be able to deduce on their own. In fact, the Gemara clearly states as much. Dever bair kaneis raglecha.
Your logic might be perfect in a place like EY, where a small minority has been exposed to the virus.
However, in many of the local communities estimates are that 70% or more have been exposed.
Why wouldn't it make sense to allow all those who were already exposed and a totally symptom free, to go back to normal life, including shul, mikvah, schools etc., while keeping those who weren't exposed or are at higher risk quarantined and protected? (I heard last night from a local Hatzolah member that the local Dr is of the opinion that this is the way to go at this point, but we're restricted by the state orders).