You can't compare.
Fitness levels and a higher degree of professionalism means that "probably" (since it can't be proved) players from 70 years ago would be outclassed.
If they were to get the same medical assistance and physio etc, who knows? Nobody.
Besides which in the 1950s, right back was pretty much right centre back, balls were heavier, pitches muddier and rules were different.
I think we can safely say that, due to advanced in health care and physical training ALL athletes from years past would be at a disadvantage in the current time.