There's a tremendous amount of inertia to be overcome before any progress can be made.
Part of this interia is fear: fear of failure, fear of success, fear of pain, fear of difficulty, fear of embarassment ... fear of fvcking fear!
People avoid what they're afraid of because they don't like being afraid - fear is painful to the soul the way the object being feared may be painful to the body.
Another part of this inertia is ignorance ... or the problem of how do you miss something you never had?
You can take a virgin and tell him all about how much better sex with a woman is ... but it's just words to him. He's never known anything other than his hand, so how can he feel deprived?
You can take a weakling or a fatass and tell him all about how much better a healthy and fit body is ... but it's just words to him. He's never known anything other than poor health, so how can he feel deprived?
I agree that once a man has better he never goes back, but until that happens ... better might as well be a figment of his imagination.
Finally, people are results-oriented ... at least in the beginning.
It takes time for whatever a person does to transform from a simple effort-reward transaction to a lifestyle or crusade. Until it does, instant gratification, however mild or fleeting, is what a person is after.
Your average gymgoer is there to lose a few pounds and be healthy enough to handle any task that comes his way - getting Arnold to come in and expound on the virtues of pain and the nobility of a life of struggle is wasted on him.
Your average guy wants a girlfriend who will give him good sex and an emotional bond - having Pook post volumes on the glory of manhood and the thrills of sexuality is wasted on him.
Whether or not there's something wrong with these guys for not aiming as high as possible is for another thread. My point is that if the goal is too big or too far in the future, the sense of need will disappear, and take a man's motivation with it.
You can try to get a mule to move by dangling a carrot on a stick in front of his nose. However, if the stick is too long - and the carrot too far away - he'll probably settle for the grass growing at his feet ... and if he's never tasted a carrot before, moving it closer won't help.