Buses are no substitute for trains even when a tortuous rail route might be slower in journey time. It is the travelling experience passengers look at...Look at the West Highland line.
The West Highland line is indeed a popular route, despite the bus offering a superior, and itself well patronised, service: An hour faster than the train between Fort William and Glasgow, more frequent and using modern (virtually brand new, in most cases) vehicles with much more comfortable seating than the trains: A much better travelling experience all round, and one that should be improved further once the Tarbet to Inverarnan upgrade of the fiddly bit of the A82 around the upper reaches of Loch Lomond has been completed.
Where the train triumphs over the bus service is in the number of passengers it can shift in one go (admittedly only a handful of times per day) on what is a popular tourist route during the summer season and the "hop on, hop off" opportunity offered for intermediate journeys on a route where the buses can sometimes run as advance reservation only due to heavy loadings, as well as connectivity with the national network.
In a similar vein to what
daodao has said, I don't think that you can write off bus services as a means to effectively serve rural areas, although I also recognise the benefit of the comparative permanence and all weather durability of a rail link compared to road, as well as the distinctly hit and miss nature of bus services in rural areas nationwide due to the unwillingness of the operators to themselves operate loss making services in lightly populated areas. IMO rail does also stand a better chance in rural areas where it serves a popular tourist destination such as Whitby and I would like to see faster journey times by rail to Whitby from the south, but I don't think that a reopened Malton - Pickering link is a particularly effective means of doing so.