Probably not, and probably yes, but there was a huge surplus of Army lorries post WW1, and a large number of Army personnel who had learnt to drive, so the driver was there, if you'll excuse the pun.
And a Beeching Mk1 need not have just been about closures, it could also have meant modernisation & improvement of inefficient outdated working practices. Some of that happened under the B4, but was enough done? Was there enough impetus to do more? Did the common carrier requirement stifle attempts at modernisation?
I guess another way of putting it would be was Beeching (and the 1955 Modernisation Plan) 30-odd years too late?