Alternative explanation: you are acting like there is no problem based on anecdotal evidence that is irrelevant to the current situation - At the same time there might be a very serious one as quite a few kids basically have missed proper school for about 2 years. Let's not even try to pretend that lockdowns have no negative effects at all.
I'm not saying there are no negative effects. What I would say is this: even before the pandemic, many students were not sufficiently "challenged". They were already moving more slowly than they could have moved. It's possible for them to catch up. They could have caught up with other kids before the pandemic too, if put in the right situation.
Time spent sitting in seats is not education, by itself. How that time is used is just as important, and we often squander that time, even when there's not a public health crisis.
Why didn't schools keep going during the pandemic, but outside or in very well ventilated buildings? This is what New York did during he Spanish flu pandemic, and it seemed to work. (It did look cold, though).
Possibly because the leadership of the associated organizations were raised in an educational system that doesn't promote critical thinking, creativity, or analytical reasoning.
I actually do think this.
"John Stuart was educated by his father, with the advice and assistance of Jeremy Bentham and Francis Place. He was given an extremely rigorous upbringing, and was deliberately shielded from association with children his own age other than his siblings. His father, a follower of Bentham and an adherent of associationism, had as his explicit aim to create a genius intellect that would carry on the cause of utilitarianism and its implementation after he and Bentham had died." https://en.wikipedia.org/wiki/John_Stuart_Mill#Biography
I realize that this is not financially realistic for application to every child. But the gap between how far we could push children and how far we do push children is often massive. We've always been "ok" with leaving many children behind.