Sure, the first six months, or even a year can be discounted as an aberration in the child development process and can be compensated for. This is year 3 with no end in sight. Do you even realize how much children develop in 3 years? A 6 year old and a 9 year old have a significant difference in cognitive capabilities and if you stop the learning process, the lifetime effect can be devastating. It doesn’t matter when you’re 30 and have to sit at home, but it absolutely does when you’re a child and your brain is developing.
And based on my long career on the corporate ladder, absolutely no one cares about whether you were a pandemic baby, a child growing up in poverty or pretty much any other non visible handicap in your life. You either know stuff or you don’t.
And since you mentioned World War 2, schools didn’t stop even in WW2, At a time when people didn’t even necessarily need to go to schools to eventually lead a comfortable life.