Originally Posted by AndrewD
I would consider that a pretty big correction. Also, I don't think you can discount the importance of the conditions in which the Kramer-era pro events were played. If 95% of the matches were played indoors on fast hard-courts that would certainly favour some players over others and really help to inflate their numbers.
Would this be any different than the contemporary "speeding up" of surfaces?
If clay events, for the most part, carried no (or little) prestige at the time (some would know better about this than me), then it's quite hard to account for slower surfaces.
The best we can do then is acknowledge that tennis was a fast-surface game at the time, because of the way the tour was organized. The business aspects of sports always control everything.