How much manual labor do you do? When I worked in fast food and manufacturing, I spent more of my spare time reading, gaming, and writing software. I still do those things in my spare time, but now, as a desk jockey, I do a lot more woodworking, cooking, and biking. I trained for a week long bike ride across Iowa. Best shape I've been in in years because of it. As I spoke with my fellow riders among the corn fields, I found a lot of professional workers. I didn't find any carpenters or plumbers or electricians.
I assume that one of the reasons you find running to be rewarding is because of the amount of work it takes to successfully prepare for a marathon. Running a marathon in anything under 5 hours is a major achievement. We do these things not because they are easy, but because they are hard. Some guy that builds houses for a living? He doesn't need any more hard work.