The risk isn't high. If the risk was high, then why would we have adopted the "flatten the curve" strategy if all the experts thought the risk was high? That strategy doesn't alter the amount of infections, it alters WHEN you get infected.
Think about it. The mortality rate is lower with medical intervention. If the same number of people are infected over a broader timeframe, then the health service is less likely to be overwhelmed, and is going to be able to treat a larger number of people.
Regardless of how virulent a virus is, it will have less lethality if the number of cases are spread out over a longer timeframe, even if they're not reduced.
In addition to this, delaying exposure-- even if exposure is not prevented-- raises the likelihood that when those people do become exposed, better treatments have been developed.
Think of it this way: say without lockdown, person A would have been exposed to the virus in July 2020, but with the lockdown, they become exposed to the same viral load in March 2021. They still get the same exposure. But a vaccine has been developed in that time; person A may have been vaccinated. And if they're not vaccinated, and become infected, they go to a hospital. Had they been infected in July 2020, without a lockdown, they'd go to a ward with 500 other people awaiting treatment. Even if the health service isn't technically overwhelmed, there's a delay in when they get seen. But in March 2021, those 500 people have been trickling in over the previous months. Doctors have been able to see them over a broader timeframe. Less delay in treatment; less mortality.
The only major problem with this virus is having the spread so fast that it overwhelms healthcare, that's the major issue, not people getting infected. If you're 24 and under, the risk of dying in a car crash is 36 times more likely than covid. For elders, they're twice as likely to die from covid than a car crash so, again, even there it's not anywhere near close to a death sentence. This, again, does not imply that I'm saying everyone go around willy nilly and not try to do mitigate the virus (as I say use the Japan strat as often as I can). But when you say the risk to life is high from the virus, then how the fuck is driving a car even a thing when you have a 1% chance of dying from a car crash in your life and the infection fatality rate of the virus is something like 0.2 - 0.3%? If the coronavirus is a high risk to life, what is the risk of life to driving when it's 3x-5x more deadly? Driving a car must be an existential threat to human life then if coronavirus is a high risk to life.
Driving a car is a high risk to life, relatively, yes. It causes an enormous number of deaths and hospitalisations. Why do you think we require people to go through months of lessons and official certification, as well as becoming insured, in order to be allowed to drive?
We've erected all the safety barriers that we reasonably can as a society. We cannot ban them outright, because social mobility would fall through the floor; society would be almost unable to function.
Society is perfectly able to function with a few months of lockdown, on the other hand.