Diesel aircraft engines and are the light jets pushing out the twins?

Roy Smith wrote:

Looking at it another way, is there some inherent reason why piston
engines are cheaper to produce?

The materials are cheaper and the tolerances (especially balancing) much looser.

Is there also some inherent reason why
they're less reliable?

The internal pressures are higher and the moving parts are constantly and rapidly
reversing direction.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.