My initial post used a 5k as my example, then you asked about what the motivation is for running a 5k so I responded to that, and you're again asking about exercise.

>Why is all motivation associated with the gym or exercise?

Because you keep asking about it. Motivation can be to keep studying late at night for school when you don't see an immediate benefit or when it's not really necessary. Maybe you have a decent job and are getting by well enough without stressing about more school. For your point about feeding your kids, having more degrees make you more employable and more likely to have a higher salary, so that's your motivation. Maybe you need motivation to clean the house. Will the roof collapse if you push off or skip a week of cleaning the bathrooms? No, but is it nice to have a clean place to live. There are plenty of non-exercise examples for motivation.