You repeat a big myth about the modernisation plan. What any debate on the Doctor has to bear in mind is that the railway at the time was still operating under Victorian legislation which required it to carry anything brought to it at a fixed published rate. OK in an era of near monopoly but the lorry in between the wars changed all that. No prizes for guessing that road haulage could cherry pick traffic away from the railway as it knew the costs of its competitor! The Big 4's Square Deal campaign of the late 30's was all about repealing this legislation so that they could concentrate on profitable flows. The marshaling yards and trip working diesels were not ordered because British Railways Management were incompetent but because the law of the land insisted on the railways being a common carrier. It was the carriage of general merchandise that made the losses - nothing to do with rural branches.
Govt insisted on the railways doing something that was loss making to provide a national service but gave them no subsidy for it. The whole history of UK railways is littered with doing governments bidding without government money. Govt didn't repeal this legislation until the 1962 Transport Act.
The modernisation plan was never fully implemented anyway, only three quarters of the DMU's envisaged were ordered. It was 20 year plan that was cut to a 15 year on three years in and ditched at year 8. Yes there were problems with implementation etc but its general thrust was compliant with what Govt wanted in 1955.
There was also government pressure to get the plan through and see its first benefits before the next election (sound familiar? :roll: ). Planning wasn't exactly good either, waiting for the Pilot Scheme to report properly would have made more sense rather than rushing the order to the extent that they did. Really, we needed the National Traction Plan
before the Modernisation Plan rather than after.
As for the closures, I can only say it was a failure of surveying and a mistake in not looking at contributory revenue. There was also the attitude to duplicate routes, in which the one 'handed over' generally died or at least got run down. How many major LMS lines closed in the London Midland Region compared with LNER lines for instance? It was also exceptionally London-centric. Hertfordshire turned from a lattice into a series of vertical stripes, making it exceptionally hard to cross the county by rail. Was that responsible for an increase in suburbanisation or a consequence of it?
Wider than that, did Beeching kill our town centres? As a consequence of suburbanisation, to get around suburbia, you need a car. Hence the growth of out-of-town shopping. That would not be such a pressing issue had we still been able to go from Welwyn to Dunstable by train.
I don't really believe that last paragraph, but it's plausible.