It was probably just used as a status title to give the sense he was an intelligent man, that knew what he was doing. And I'm sure he did in his chosen field in ICI.
Unfortunately being well qualified in one field doesn't make you expert at everything, or even have any element of common sense, or a rounded approach. Beeching admitted he knew nothing about railways.
Nevertheless, Beeching was only following government orders to 'make the railways pay'. Leaving aside they were basically worn out because of the war - we'd have lost the second world war without them, there was no motorways at the time.
Cost benefit analysis wasn't very well understood at the time, and the idea that everything 'should pay' is actually ideology in the field of public service - the same isn't applied to other things.
If you look at the history of public spending in the country over the last 300 years the vast majority is spent on the military, for expansionist polices, land grabs or to settle politicians idealogical conflicts.
http://www.ukpublicspending.co.uk/uk_year1890_0.html
No money was really spent on health and education until the Victorian period, then only a fraction of the military budget, and nothing much on transport until after the war.
If you allow markets to run on their own, its rather like a game of monopoly, and ever increasing wealth is shifted to the top. This is fine to a point, but divided societies are not happy ones nor are they very efficient - as you are wasting a lot of talent as people nearer the bottom of the pile do not get the opportunities or resources to make the most of themselves.
In the case of the railways, a lot of the closures were never really looked at from the point of view of lack of connectivity, and many parts of the country have never really recovered since Beeching and remain backwaters.