It's true that the tube driver must 'only' obey signals and battle endless boredom, especially in the tunnelled sections and keep to speed limits,
Not so - on several lines with Automatic train operation systems, the driver merely needs to check there is nobody jammed in the doors, before he simultaneously presses two button to start the train into motion operation. Sure, they do more when it all fails but Victoria Line has always been capable of driverless operation.
There are records of trains leaving without the driver after a misfortune with a taped marble to cover one button (as pressing two buttons was too complex/boring/hard for one individual) and the mechanical failure of the second button resulted in the train moving to the next station on its own without its driver who was not even on the train.
On older signalling system lines they are undoubtedly needed but as has been said, it is in no way a highly skilled job. The only reason they are highly paid is decades of Ken Livingstone awarding them above inflation pay rises and their own ability to bring the city to a standstill.
Pilots could do a train driver job as long s they didn't mind getting bored but there is not a train driver out there who could be a pilot - for starters, pilots have deal with other people in a reasonably polite and intelligent manner.