IO540 touches on a point that gets to me. These "1960s tech" aircraft that we fly are fine, they're safe, and they don't compare with the techno-toys we have at home. Fine. When I go for walks, I don't need much tech, either.
But... even this low tech level needs some pretty well honed skills to keep on top of it. Today, two of us flew to Le Touquet for fun (and for lunch). We encountered some thin stratus along the way - no problem: we've both done plenty of this before so we told ATC and climbed above it.
Meanwhile, there was another PA28 a few miles ahead, on the same route as us, who was clearly having trouble coping. His RT was snatched, and whenever we saw him (below the clouds we were above), he was at a different height and going in a different direction. We worried, on the basis he seemed to be "on the ragged edge".
He got there and back OK, but I would have been very nervous if I'd been in the back of that aircraft. He was a long way "behind" it.
My point: latest tech (devices like GNS430) would probably add to his stress level, because there are so many buttons to press and so much to do and know before it starts to "help". The 1970 Cortina wasn't beautiful, but it was basic, simple reliable motoring with no sneaky bits to bite you and not many buttons to press.
We can "simplify" aircraft (up to a point), but the pilot still has to be able to "manage" this device in 3 dimensions, while navigating and communicating. The clever bits come later. I made my daughters learn to drive on the Missus' 65HP banger, not my 210HP batmobile, for similar reasons.