What was wrong in suggesting a puddle suit? The children of those who did buy one will have had good use out of it.
Someone I know with a three year old, who has recently started going to a nursery part time, believes that lockdown was extremely beneficial to her. She has learned so much from being with her parents, especially her accountant dad whose work was mostly done from home. The girl has emerged very articulate and confident. Now that she's at nursery, she loves it!
The other problem was childcare for parents who had to go out to work during lockdown. That must have been so unreliable for many, no doubt a lot of child care providers shut down altogether for a while.
How a child develops will depend a lot on the parents, some are better at teaching and encouraging than others. However time passes quickly and children are great at recovering and adapting, far better than adults.
Time will tell but I doubt there has been any permanent damage to children. That may not be true for adults who have lost jobs, been seriously ill, etc, and economically we are in a bad way.
I don't honestly know how else the pandemic could have been managed though no doubt there are many theories; hindsight is all very well. Nobody dreamed it would last as long.