In countries that had lockdowns, children and young adults arguably suffered worse than any other group. For a ten year-old, that's 10% of their life "gone". Children, teens and young adults have foregone life milestones, missed opportunities and friendships. Instead they have been charged with a ridiculous anxiety about something that is harmless to them.
It is comparatively inconsequential for the elderly to isolate.
Opening everything up now, without a adequate vaccination rate, would just put them at a huge health risk. Right after the social impact they already had.
And the social impact, IMHO, affected everyone.
We have to reach a point where Covid becomes endemic and we, people, society, are good to love with it. We will reach this point quicker the faster we vaccinate everyone. I guess we can agree school closures are not so good thing, right?