It depends what you mean by "our best". We try to reduce the risk without sacrificing too much. Wearing a seatbelt is trivial, because there are basically no downsides. We could also half all the speed limits - that would reduce the risk a ton. But we don't do that because people like to drive fast because they (up too a risk balance) value their time more than their life (sounds rough but that's basically what it is).

It's the same with pandemics. Of course a lockdown prevents a lot of deaths, but at what cost? Is it worth it. We wouldn't half all the speed limits to reduce risk?

I'm not against lockdowns in general, for example during the first covid wave because it bought us valuable time to figure out how we proceed, but a lockdown is (figuratively and literally) high cost.