They didn’t catch on for all the reasons you state: * High RPMs are bad in a aero engine. There are very few (no?) propellers on GA airplanes which operate ab

They didn’t catch on for all the reasons you state: * High RPMs are bad in a aero engine. There are very few (no?) propellers on GA airplanes which operate above 3k RPM, so you need a reduction gearbox. That cuts into your weight savings and also reduces reliability. * Vibration isn’t a significant concern for GA airplanes. * Throttle response is not a significant concern in GA-sized reciprocating engines. * Poor efficiency is a major problem because 1 lb of extra fuel is 1 lb less payload. All airplanes are limited by takeoff weight. (The 3000 HP-class radials built by Wright and P&W at the end of WWII are some of the most efficient reciprocating engines ever built) * Maintenance is a huge concern for GA owners because labor costs $200/hr. Airplanes with 1200 TBO engines sell for a noticeable discount to airplanes with 2000 TBO engines.