Well, considering the course of tennis history they (we) were not unreasonable to think that way. How was anyone here to know that not 1, not 2 certainly 3, and arguably 4 players were going to rewrite the rules of what was possible in the sport?
If I'm right, Tilden won 5 slams after turning 30, that was almost 100 years ago, Rosewall and Laver won 4 apiece after, turning 30, that was going on 50 years ago. Since then I think the record is 2 By Connors and Agassi. Djokovic and Wawrinka are both at 2 now, with Novak almost certain to add to that number, Rafa's on 3 and could add to it, Fed's on 4. They're literally rewriting history, certainly Open Era history.