Well put Art and I wish you good health as you look toward your future, may you and yours enjoy it.
As an interesting point to longevity of gas engines and hard use. I captain an air-boat a couple days a week (mostly during the cooler tourist months). cool way to pick up a few bucks and the tips are great, I call it my gun show money.
My friend Bob has two air boats
Airboat Tours in Vero Beach Florida - Capt Bob Airboat Adventure Tours and we run the snot out of them. These are cast iron big-block V-8's making 425hp. airplane engines would not like the use/abuse we give them and are 3 times more expensive to buy and repair. Full power starts from idle to WOT (4300 rpm) to next spot then idle for a few min then WOT again. We use 5-8 gal of fuel per trip and run from 4-6 trips a day, each trip is an hour.
The oldest boat is in for an engine rebuild (it was running fine but he wanted to not have any issues coming up to the next season, and needed to spend some money or pay more to .gov) The motor has 4250 hours on the Hobbs,runs fine and uses a qt. in 5 hours use, don't let anyone tell you that gas motors are wimpy. They are NOT quiet motors.
Regards.