Yes you are right. But working men in the North East of England at that time did exactly that - work their socks off. So the idea of becoming a professional bike rider would have been laughable. Stan was a painter and decorator. A contemporary of Stan's in North Yorkshire, Brian Trippett said in an interview "I didn’t race in the Tour de France for the same reason. I was asked to twice, in 1959 and 1960. But it would have meant using up all my annual holiday." You get the drift.
But now the world is different, and many of the excellent British riders who rode superbly back in the day would have a host of different opportunities now, particularly with the dominance of British riders in track cycling and grand tours.
Opportunities have dropped temporarily since the UCI reduced the team size from 9 to 8 in an attempt to reduce the number of crashes. It has actually had no effect in that regard, so lets hope they increase the team size back to 9 and get more pro riders on the grand tours.