Not having any children myself I cannot speak from experience. I can though speak from memory, now over 50 years! of playing with my clockwork Hornby 0 gauge. Winding it up was not a bind, there was no alternative.
Recently I went to a local toy auction and there is quite a bit of Hornby O gauge coming on the market, most of it still working. Sets are not cheap, but actually about the same as a modern 00 gauge set.
What can be cheap is the old tinplate track. Often in big jumbled boxes. I bought such a box at the auction, around £40. It was a mixture of Hornby, Gamage and unknow and it stes of repair from excellent to nearly scrap. Enough for ovals of double track and single track. There was also Hornby three rail. As well as track there were points.
I only wanted the basic stuff, so sold the three rail. One Hornby twin three rail rail cross over point made enough to pay for the whole lot on eBay. The rest made me a profit! And I still have a load of decent Hornby tiplate track.
I originally bought to try out Meccano locos
but am now working on some further DIY efforts at various scales.