No Evidence just a theory. What if Covid was supposed to wipe most of the adult population leaving only the children? They are mostly immune and the elderly were hit hard. Somehow it was changed and the middle age were spared. If you kill off the adults you have free access to all those abandoned children and you can start their retraining immediately. Getting rid of all those pesky traditions and history. Just erase it all and rewrite it to suit you. They can't kill off the entire population because they would have no servants. Kill off the adults and start over with the most impressionable children.
That possibility exists too. I'm just reminded of the Denver Airport murals with all the children. Not many adults in their utopia.