He's not asking for cheap alternatives, he's asking why aviation
costs are
so disproportionate (i.e., why a 25 year old aircraft cost more
than it did
new).

supply and demand.

It's liability, too. Everyone tags on "x" percent, just to cover their
perceived risks.

Also "economies of scale". You'll find similar (expensive) situations
for boats and other niche items that don't have a huge market base.
And airplanes don't rust, meaning they can last longer than cars.
They do corrode, but that usually takes longer.

Jim Rosinski
N3825Q