I don't follow the 'feeder' series very closely.
Is Mick without talent, or was he brought into F1 before he had a chance to hone his skills? F1 really became obsessed with bringing in drivers young. It worked out with Kimi, Vettel, Alonso and Max. However, none of those four were 'locks' to be champions, and were brought in just to see how they'd do. Button struggled a lot early, and without the Honda/Brawn saga, he probably would have left the sport with a single win.
But McLaren waited on Hamilton, and that gave us one of the most sensational rookie seasons of all time. Michael Schumacher was 22 when he first raced F1, and that was as a replacement with zero expectation for results; not the pressure to be a multiple world champion carrying the weight of the sport for a decade.