Mike, sounds like a bad day that could have gotten worse. Way to keep your head. I dont know about older though, I hunt elk with a couple brothers in their late sixties and I'd put those guys up against probably half of all 30 and under guys that you see around town, just plain tough and in shape, and experienced to "keep their heads" through just about anything.
Great story, but have you thought about a rope ladder atached to the boat along with the vest? maybe mount a piece of 4" pvc along the top rail of the boat somewhere and roll up a simple rope ladder a couple feet long and stow it in the pipe so lures and such dont get tangled in it with a cap that has a good handle. If you fall in again, or someone else does, just reach over the side, pop the cap, pull out the ladder and up you go.