I understand your point about the 70+ population, but that population should not be unduly pressured to self-isolate any longer than absolutely necessary either.
That age group, by the way, would include quite a few state/federal judges, state/federal legislators, POTUS himself, etc, and of course a lot of otherwise healthy grandparents all around the nation.
My thoughts.
A Freeper had mentioned healthy 70+ year olds not isolating. I would be on board with that.