In my opinion the main difference between those on the top and normal drivers isn´t just the knowledge about being fast it´s how you execute it.
I´m doing online competitions for about 15 years since GT4 now and I´ve done thousands of hours trying to get faster.
One of my favorite track is Suzuka and even I did several thousand laps there I´m still about 1 second off the World Record on the recent Race C ( P.70 at the world rankings).
Maybe I could have a luck shot and gain another 2/10, there´s still much time left. In theory I know how I could be faster from watching replays of the top guys but I can´t do it on the track. There are such small margins ( braking 2m later, be off the line by 20 cm etc.) which cost you the last tenths.
When I´m lucky I can match them in one corner in one of 50 tries but I´ll lose on the next one. They have those perfect corners one after another.

You can see this in my comparison on the Nordschleife time trail where I compared my lap with Igor Fraga.
I´m quite sure it´s not only about the training, the aliens on top have some physiological advantages. Maybe they react faster, move smoother or are more sensible. I don´t know what it is but if you have this talent you can get to the top with enough training, if not you will reach your limit 0,5 sec., 1 sec., 2 sec. behind and won´t get any further.
That´s something I accepted after many years chasing ghost cars.
