IMHO, this man was by any standard (besides F1 titles) a better driver than Rosberg (N and K), Raikkonen, Button, Villeneuve (J and G), Damon Hill, Hakkinen, Mansell, Piquet, Alan Jones, Jammes Hunt, Jody Scheckter, Lauda, Hulme, Brabham and Farina, just to name less efficient drivers who won championships. And newbies like Verstappen and Leclerc are very far behind in efficiency. He had podiums on 35,8% of his races and won 23,8%.
Maybe his mischance was to compete against monsters like Ascari, Fangio and Surtees at their best. Maybe he could win a championship if raced the 2009 Brawn or some other instant-win car... we will never see it, but deep in your hearts you all know that he could.