I see this criticism of today's baseliners - oh they would have been screwed if conditions were faster. The data point that supposedly supports this is "Well every time they play on fast courts they don't seem to do well so clearly they are not capable of adapting". Adaptation is not instantaneous - it takes time and people forget the concept of return on investment. Today's baseliners are so good at the baseline, because they have spent the majority of their time practising those kinds of rallies rather than S&V. They can afford to do that because 80-90% of courts reward baseline play. If only 50% of courts rewarded good baseline play, the same baseliners of today would spend more time honing their S&V skills. Yes perhaps there is some innate ability needed to be a good S&Ver. But a lot of it comes down to technique. And technique comes down to practice. And you only practice something if you think the time spent is worth the effort. A big tall guy like Del potro might have been a complete S&Ver instead of a powerful baseliner, had conditions been different.