Planes have leap frogged technologically. Envelope protection, synthetic vision, airbags, parachutes, 200-340 knots with efficient high performance props, fitted alcantara leather seats that would be at home in a BMW, with dual automatic climate control zones, some of the new ones can even land themselves. Can't say that today's planes have much in common with planes of the 70's. Some OEM's have stayed locked in time, but that is the fault of the OEM's, not the lack of progress.
Here are just a few props that were not even considered possible in the 70's 80's, 90's and even the early 2000's for some of these aircraft. Fully digital cockpits that seemingly see through clouds, digital autopilots that seem to ride on rails, and electronic stability programs that can rescue an out of control pilot, and some that will even land themselves with no pilot input, all while talking to ATC, squawking 7700, checking winds and weather, to pick the best place to land. 300+ knot propellor driven aircraft that can cross the country in half a day. These aren't 1970's Cessna's Pipers or Bonanza's. Some of them are pretty pricey, but have you priced luxury SUV's or homes lately?