There are fast court only ponies and clay court only ponies.
Without collecting the statistics it seems those who win any of Wimby, US, and Aus are far more likely to win another distinct slam from those three rather than win the FO.
Likewise, those who win the FO often really struggle to win any of the other three.
So that's why I see the playing surfaces as fast courts and clay courts and some players as fast court only ponies and others as clay court only ponies.
It takes a very special, no an exceptional, player to win more than one FO and any multiple number from Wimby, US, and Aus.
Bjorn Borg was 5 and 6 or was that 6 and 5. Anyway Borg was a world beater going from one extreme to the other. Plus he lost a few US Open finals so he was no mug on hard courts either. Truly exceptional.
Fed 2010: Federer aged 28 16 Slams(inc. career slam) vs Sampras aged 28 14 Slams(no FO)