build up societal immunity, while strictly protecting the vulnerable. Then in just a few weeks, a huge segment of the population will be theoretically immune, and so the little ones won’t be virus vectors anymore. The increasing immunity in the population will theoretically blunt future outbreaks and limit spread.

I would think those under 40 could return to work, with some flexibility in those between 40-55 or so. So you get a chunk of the economy back up and running, kids back in school, sports back going with limitation in attendance of older spectators, all while building immunity in the population.

Seems very reasonable to me and much more sustainable.