Don't be a tard. Why doesn't he have a slam and an olympic medal then?
Because he is mentally weak. - Oh wait, no, apparenty according to his fans he's a warrior who always gives everything on court and a mental giant so that can't be it.
Maybe he's had horrible injury problems that affected his progress during his prime years. - Wait, no, that was Del Potro.
Maybe he was just unlucky to face superior opponents in his runs and that's why he doesn't have those titles. - Wait, no, Del Potro faced the two greatest players of the XXI century to win his Slam (with Federer going for six in a row) and world #1 and #2 for his Olympic medal.
Maybe, just maybe, Del Potro is a far superior tennis player after all.