I don't claim to have a recipe that sustains itself, I just find that my energy diminishes if I'm not doing a project for its own sake.

If after ten years the spark was gone we should be happy for that ten year contribution, but I don't think there's any reason to assume that money would've prevented the problems that motivated him to step down. Maybe it could incentivize him to muscle through after the magic was gone, but that's a different sort of thing.