I was a flight instructor - single engine, instrument, multi engine, instrument, commercial, flight instructor, and advanced ground instructor. I LOVED to teach flying. I owned several airplanes, both in partnerships and by myself. As others have said, it ain't cheap.
I did some digging when I was considering buying a new twin (a few years ago), and one thing absolutely astounded me. MOST of the cost of a new airplane was in manufacturer's liability insurance for airplanes made in years past.
We've all heard the stories - a SEL rated pilot takes off in weather that turns into IMC. The pilot crashes into the side of a mountain because he lost control of the aircraft. The FAA says the cause of the crash was "operation above the pilot's experience / rating". Truly sad. This is what claimed the life of JFK's son a few years ago. But the civil jury found the manufacturer liable because the aircraft broke up upon impact, and awarded a huge sum.
This is the problem - manufacturers find it difficult to improve a design, because every improvement can be considered an admission that the previous version was flawed.
I have some great memories of my Dad and I flying in my 1941 Taylorcraft. The seat was a sling of canvas between 2 boards. No electrical system. Just seat-of-the-pants flying, navigating by following the roads below, and finding a restaurant serving great pancakes and bacon.
it's truly sad that the lawyers and large jury awards have almost completely killed general aviation. I certainly hope they're sleeping well at night.