Turns out that drivers who are good get recruited by good teams and score good points for them, putting the cars at the top of the constructors' championships...
Other top 10 drivers include Michael Schumacher who drove 15 top 3 cars in 19 seasons (the other 4 were 4th, 4th, 4th and, in his last season, 5th), Alain Prost who drove 12 top 3 cars from 13 seasons and I'm sure if Juan Manuel Fangio, Nino Farina or Alberto Ascari had been driving a constructors' championship too, they'd have been exclusively in top 3 cars...