F1 drivers, just like any other drivers need to constantly train and just like any other sportsmen they cannot constantly operate at their peak performance levels. They cannot be the very best in the world only because "They have talent". Lets describe talent then, shall we?
"Talent" in reality is a set of specific neural networks, specifically optimised for:
1) making all needed calculations i.e. grip limits estimation possibly accurate, in possibly shortest time;
2) synchronising tens of thousands of muscles with very limited margins, in terms of speed, timing and precision;
3) recieving input data at much faster rate than most men (for example, most men have visual data refresh rate of about 4-5 hz, smoothed with interpolation; in that rate lowest possible reaction time could be about 200ms - and thats a lot of time in F1...)
and so on...
In F1 terms anyway that is.
In case of young drivers (kids), "talent" can be considered as brain's ability and capacity to create and tune more less correct for the purpose neural connections. Kid enjoys some activity when its brain decides they can be good at it and encourages for more training for example by stimulating production of apropriate hormones. If after some time of one man's training maximum level is achieved and the other one is still improving, then the latter has developed better suited neural net for the task - is more talented.
Unused neural networks are being slightly reconfigured and/or can be used for completelly different tasks. Thats one of the reasons why F1 drivers need to train - to keep their brains "tuned" for optimal performance in some sport.
The other thing is they need to adapt to every single change of conditions - like car behaviour change. Brain predicts car behaviour using a neural network models. Like any other mathematical models, it has defined structure and parameters. Training is needed to adjust the parameters in the model for better representation.
If modelling of a car in driver's brain has wrong structure then it cannot achieve convergence with the real-world model. That's probably why a car can suit a driver or quite the oposite as we have seen in case of Massa's replacement i believe. They just couldn't tune their models to it properly without reorganising their brain...
So keeping brain in good shape is one thing - the other is physical fitness. If Your body simply can't keep up with what Your brain want's, You won't be at Your best, regardless of how "talented" You are.
There's quite a lot of influence of psyche too! Most of men could probably do somersault straight away, even if they spend most of their lives in front of TV. Their body could that is. But i seriously doubt ANY McDonald's everyday visitor would agree - lack of confidence would result in impressive failure probably...
My point is - to be at their best F1 drivers need to keep their brains, bodies and psyche in perfect shape. And that most certainly can't be achieved without hard WORK. It looks like Massa is currently missing one/some ingriedients, wonder which (one)?
PS. Sorry for long boring post