The Beeching - Marples legacy should be tought in schools as a warning from history.
As should the prior 10\20 years where equally bad decisions were made in terms of massive amounts of money wasted on new engines and rolling stock that helped cause the crazy losses reported that contributed to the perceived need to reduce the losses, hence reduce the railway network, hence the Beeching report etc.
First we had "standardisation" of the steam fleet, then even before that was completed we had diesels and electric engines and multiple units being built, then even before completed, the lines were closed. The amount of stock that was scrapped just a few years into it's expected useful life of decades was really criminal!
Funnily enough it was forward planning that came undone by a lack of forward planning. One arm not knowing what the other was doing - one group planning to replace all steam traction with diesels/electrics whilst the other arm aware of and planning for the decline in freight and passenger traffic. Neither really knowing (or perhaps not caring) what the other was planning for!
We had whole fleets of "smaller" diesels that were to replace the steam tank engine fleet for small/local freight. But small/local freight was already in massive decline, so the logical answer would have been to keep the steam tanks for a few years longer - but, oh no! can't have that can we? We had the undue haste in having to scrap steam, so for a very short period, we needed the replacement small diesels. Within just a few years, we scrapped the diesels that caused the steamies to be scrapped a few years earlier. Crazy!
Railway history should definitely study the mistakes of the 50s just as much, if not more, than the mistakes of the 60s. We all know about Beeching, but in my opinion, the policy to standardise the steam fleet by building vast numbers of new locos, and then to build engines and rolling stock for lines destined for closure, was just as ill conceived.