Oyster works because the model essentially serves a single city (with exceptions). Said city has a vast, dense population with huge public transport needs. TfL oversee this en-masse which allows for integrations, although many occur naturally due to the frequency of the services. That doesn't work on an intercity basis, let alone at a regional and national level. If you take something like a bus service to Alton Towers, imagine the number of train services that you would ideally link up with at Stoke station - not local services either, five hour WCML services spanning the country which are already notionally aligned to connections at other interchange stations along the 400 mile route.