What happened to the motivation?

Why is it that so many salespeople start their selling careers with a great deal of enthusiasm - truly motivated to grow, to succeed, and to advance their careers - and then, somewhere along the way, the motivation fades, and the "career" becomes little more than a job... a way to make a living?
 
What happened to the motivation?
 
Motivation is not a capricious feeling that comes over us when we least expect it or disappears when we most need it. It's a feeling that begins, and is sustained, by a process which we control - a process that starts with, of all things, curiosity.
 
When you're curious about something, like a new job, you want to know more. So, you seek out information - knowledge about the company, the products you're selling and customers to whom you're selling them, as well as the competition you're selling against. The more you learn, the more interested you become; and the more interested you become, the more you want to learn.
 
So, what brings this self-perpetuating cycle of growth and motivation to a halt?
 
At some point, usually around the one-year mark, you realize that you're doing a fairly good job. You're earning a living; you're beginning to consistently make your monthly quotas; and you're even giving advice to other salespeople. You still have the opportunity to participate in training and obtain additional education, but you don't seem to feel the need. And, with family responsibilities, community activities, and of course, the obligatory (?) golf outings with your key customers, you can't find the time.
 
Several years pass and the job has become just that, a job - something you have to do, rather than something you look forward to doing. Your five years of experience has actually been one year's experience five times over. That's because the moment you stopped learning, you stopped growing. And, when growth stopped, so did motivation.
 
So, how do you maintain motivation (or regain it if it's slipped away)? You must continue to learn, to enhance your skills, and to gain knowledge about your company, your marketplace, and your products. When you continue to learn, you maintain interest, facilitate growth, and most importantly, perpetuate motivation.