I have a different theory, but it's mostly a cheeky, incomplete one. I think infants start out not understanding conservation[0,1] and there is some programmed primitive instruction in humans to understand conservation. It would explain why modern physics exists, and would also explain why kids are obsessed with garbage trucks -- because where the hell does trash actually go? One you understand conservation enough to ask that question, it is inevitable to be obsessed with garbage trucks.

[0] https://www.alleydog.com/glossary/definition.php?term=Conser...

[1] Things that do not grow or shrink change over time, even if they're redistributed.