'how many classic majors would Laver have won, had he not turned pro at the end of 1962.'
Sad. Take away '06-'10 from Federer & '94-'98' from Sampras and both their GS totals nose dive. Pointless to do so but still highlights how great Laver was.
There's no point rewriting history, though it is fun. 1997 without Graf falling apart for instance.