The complexity of airspace, and the associated importance of R/T.
Oh I dunno... One of my planes does not have a radio, and I rarely use the radio in my other planes! The airspace only gets complex when I go near Toronto - so I don't do that much!
An old time pilot, after he fought his way through traffic to the airport, paid to park, found his yellow jacket, got through security, and paid several dollars per liter for gasoline, might be thinking back to the good old days with fondness!
THE Cessna 152 I paid $22 per hour for in 1978, is still available for rent for student pilots - for $145 per hour now!
I know the technology is out there, and was reminded when I flew A G1000 Cessna 206 a few days ago, but aside from a GPS/Comm I installed in 1989, my Cessna is about the same as it was when it left the factory in 1975, which was pretty close to the way it was offered in the mid '60's. I think I'm stuck in an aviation time warp, when I tell people that I own a "newer" Cessna 150, and it's 44 years old! And, I like it in the time warp! I read more and more about self flying airliners on autopilot, who cunningly prevent their pilots from actually flying them, and cars that steer themselves down the highway, until they don't - and the time warp backward is looking pretty good!