Indeed, there have always been huge disparities between urban and rural. Costs and reliability often rise and decline respectively when travelling across county borders and out of town/city to rural areas.I have no idea really. It's been a long time since I commuted on buses, but I'm sure I was paying between £2 and £3 for a return fare in those days, nearly 20 years ago. I remember some time in 2008 ish Arriva stopped running a lot of the evening services in Luton and a company called Grant Palmer took over, which meant anyone leaving town after 6 was shafted as return tickets weren't valid across the different operators. Things got expensive quickly but this was almost exactly about the time I changed career path and had to buy a car anyway (Grant Palmer would later shut down the evening routes to my area of town altogether as unprofitable).
Like a lot of these things I suppose there isn't a single answer that applies across the entire country given the disparity local economies. With different degrees of poverty, types of job, the local geography and whether masses of people are travelling in a single direction or not (or even travelling at all), there isn't going to be a single standardised demand for bus routes or ability to fund them.
It does seem overall that this is one of those Tory traps left for Labour, totally unfunded beyond 2024 and forcing Starmer to either let prices crank up immediately or make some unforeseen spending decisions. Is a raised cap the best response?
A £3 flay fare for a trip from Bristol to Weston-super-Mare is probably a bargain. A trip from the city centre to Eastville less so.