There was a different version of this discussion earlier this season during a Speed TV (US) Formula 1 telecast. The commentators - I think it was Varsha and Hobbs - were talking about the skills required to drive a 1950's vs. 1960's vs. modern F1 car and concluded there was really no comparison. There's a vast difference between what was required of Fangio (no power sterering, no seatbelts, oil spewing at you from the engine out front), Jim Clark (the car is all power and no grip, it's as likely to go airborne as hold the turn) and Alonso (deep knowledge of aero, ability to manage all the computerized engine settings, work with the engineers on software-mediated balance settings)... One man wouldn't have the skills or experience to compete effectively in the others' eras.
Re: airplanes - my impression (which owes a lot to A2A and Accu-sim, plus a lot of reading) is that in the 1940's, at the end of a long technology race, powerplants and aerodynamics had outrun the pilot's ability to control them, so as a pilot, you were forced to spend a lot of time keeping the engine from blowing up and the aircraft inside its performance envelope. Development after that involved simplifying the mechanics (jets are easier to operate than radial engines), then automating the systems to allow the pilot to spend more time flying, or managing the flight, or in the case of a combat a/c, fighting. But as others have pointed out, the systems require knowledge and management themselves. So basically there's been a change in culture - from wrestling with big unruly mechanical systems to mastering the intricacy of computer-based ones.
For my own personal enjoyment, there's something about big unruly radials. Call me Fangio...