The Main Point
is that Laver wouldn't have found completing his Grand Slam on 3 surfaces rather than 2 any more difficult at all. In fact, given his talent I suspect that he would have found it a bit easier actually. (Some have said that his game is highly suited to Hard Court). Remember Laver won over 30 outdoor hard court titles.
I wonder if he now wishes that some of the Slams would have been on Hard Court during this era - maybe he would have won more still?