but it doesn't seem sustainable
It's not. But the theory is that if you know 100 people are going to get it, you try to have 1 person get it per day across 100 days, as opposed to all 100 at once.
I too wonder what's going to happen on the other side of the curve. All it takes is one to start it all over again. In a sense you almost have to expose people in waves. But if the mortality rate is not 0%, nobody will ever accept that.
We are likely going to be in some state of shutdown/lockdown through the end of school IMO. It may be on-again-off-again but if we just unfurl the banners I think it'll just ramp back up.
South Korea is not on lockdown. They're just being proactive. Check this article it's pretty good:
How Italy, South Korea differ in tackling coronavirus outbreak
Seoul and Rome took different approaches to combating the spread with significant contrast in outcomes.
www.aljazeera.com
They chose not to bury their heads in the sand and they tried to get ahead of the curve. And they use data to try to address the issue. I know people here will freak out at privacy concerns but it comes down to the question of what people really want most. Privacy or health?