Moreover, if Richard Feynman's biographical essays even slightly typical, mid 20th century kids actually did do a fair amount of experimentation.

Remember machinery in the mid 20th was simpler but less reliable, so a kid with the latest gadget, whether radio, hot rod or model rocket, had considerable incentive to tinker. In fact, I suspect tinkering/hacking is main story for boys of that era and science was more of an offshoot.