Not to mention that after the first couple of months, Covid cases are now nicely distributed amongst younger populations as well. Fatalities are still concentrated in older people, but cases are still widespread across demographics.

The facts are staring everyone in the face: when countries started weakening their lockdown procedures, cases started going back up. And nobody's been willing to go back in full lockdown, for various reasons. And so cases are going up a bunch.

Meanwhile Vietnam had some cases in fall/winter, and _immediately_ locked stuff down, shut down universities, and quarantined people who had even a bit of contact with people in positive cases. The stuff was taken seriously, and numbers stayed low because of it.

Maybe the US and Europe "can't do it" because of a lack of political will etc. But it's not physically impossible.