How? There isn't any chicane at the end of the DRS straight, so overtaking is possible. It's all about setting up the final corner. Maybe you think that it's impossible to follow in a high speed track. I'd say that a lot of the high speed corners, following is not an issue, because the corners are long. In long high speed corners the outwash goes towards the outside of the turn, the following car can avoid the downforce robbing outwash by staying slightly closer to the apex than the leading car.
Of course, easier said than done, but if passing is too easy then it's also boring. You have to admit that it's more exciting to see a driver try to create something out of nothing, than to just see them whiz by. Also, consider the speed of the cars onto the main straight, that's a long straight and the cars are going well over 250kph passing the rumble strip on corner exit. Meaning slipstream plays a big factor, especially combined with DRS.
I think overtaking in Mugello is easier than overtaking in Imola because Imola's straights end in chicanes.
The height of cultivation is really nothing special. It is merely simplicity; the ability to express the utmost with the minimum. Mr.Lee