Just to be clear, there's no specific "road tax" in the UK - it was abolished in 1937. Instead general taxation (e.g. income tax) pays for roads.

Your point about places becoming further apart has been made by Cory Doctorow who refers to it as "geometry hates cars".

Edit: found the Cory link - you might find it interesting, but I suspect it's detailing what you already know

https://thewaroncars.org/transcript-episode-79-the-end-of-ub...