This is how I understand the ideas outlined in the video, and I am happy to be wrong.......
There is an absolute limit as to how good a batsman can be due to the constraints of human biomechanics, reflexes, eye sight, and depth of concentration. The greatest batsman from each era (for the sake of argument the 1920s onwards) are all very close to that absolute limit of excellence.
The reason that it is no longer possible to achieve an average that is twice as good as everyone else is because everyone else on the cricket field is better at playing cricket. Better batsman, better bowlers and better fielders. In other words, because everyone is closer to the absolute limit of cricketing excellence it makes it far more difficult for the likes of Sobers or Tendulkar to stand-out, to be a true statistical outlier.
The fallacy that Bradman is about twice as good as every other great batsman is a fallacy because it makes the false assumption that there is no absolute peak that batting can reach. Or if there is, then that peak can some how be moved. It cannot.
In real terms, Bradman, Sobers, Lara, and Tendulkar have all pushed the skill and art of batting to its absolute limits, and therefore to say that one is significantly better than the other doesn't make sense. To say that one great batsman is about twice as good as another great batsman appears rather silly.
I have a book which contains an interesting study along these lines. Between the Wickets, by Surjit Bhalla, includes modified averages based on all matches being normalised as if they were played at Lord's against a moderate attack (revised average over 50):-
82.90 Don Bradman (99.94)
62.40 George Headley (60.83)
60.25 Graeme Pollock (60.97)
58.76 Jack Hobbs (56.95)
55.76 Viv Richards (52.62)
54.33 Garry Sobers (57.78)
53.23 Everton Weekes (58.62)
52.64 Dudley Nourse (53.82)
52.24 Gordon Greenidge (48.32)
51.40 Aubrey Faulkner (40.79)
51.55 Greg Chappell (53.86)
51.40 Len Hutton (56.57)
50.82 Herbert Sutcliffe (60.73)
50.56 Allan Border (52.80)
50.55 Walter Hammond (58.46)
50.40 Ken Barrington (58.67)
The book was printed in 1987 so some players (Richards, Greenidge, Border) would play for more years and finish with a different average. Bradman's average drops significantly, but he's still 20 runs ahead of the next best.
The revised bowling averages were calculated along similar lines (revised average under 20):-
15.59 Harold Larwood (28.36)
16.13 Allan Davidson (20.53)
16.29 Clarrie Grimmett (24.22)
16.77 Bill O'Reilly (22.60)
17.02 Maurice Tate (26.16)
17.04 Neil Adcock (21.11)
17.68 Jim Laker (21.25)
18.16 Fred Trueman (21.58)
18.16 Hedley Verity (24.38)
19.06 Keith Miller (22.98)
19.28 Peter Pollock (24.19)
19.60 Alec Bedser (24.90)
19.65 David Allen (30.98)
19.91 Ray Lindwall (23.03)
Sydney Barnes goes from 16.43 to 25.94.
Somewhere, fredfertang is smiling...