I think the answer lies in the most important aspects of this sport.
1. There are no gray areas- you either win or you lose. In our current culture that stresses, "we are all winners," wrestling can be a cruel wake up call- for kids and parents alike. If a kid keeps losing it is harder and harder to keep coming up with new pep talks.

2. The sport only gets tougher as the kids get older. There are fewer "easy matches" for 12/u vs. 6/u thus there are fewer opportunities to taste victory unless you are pretty good.

3. It is an individual sport. Having been on a losing football team and a winning wrestling team in high school I can testify that there is a difference. If the football team won we were ALL happy and if we lost we comforted each other. If the wrestling team won but I lost my match, it was still hard to jump up and down with glee.

4. Besides being an individual sport, it is a very personal sport. Having run track and field to a fairly high level of competition, I can tell you that getting beat on the track or in the long jump pit was very different than getting pinned (or just losing) on a mat in front of your friends and family.

5. Wrestling is hard. Losing a wrestling match usually hurts more than your feelings- it physically hurts.

6. Like marathoning I believe there is an intangible in your personality that you either have or you don't. Many run a marathon to say they did it at least once but few have that "something" that makes them want to do it over and over.

From this I would submit- wrestling simply isn't for everyone. We shouldn't try to force it on our kids. Encourage them to try it and help them all you can when they do, but once they have tried wrestling let them make the decision. Telling a kid to keep wrestling and they will learn to like it is like me telling you I can teach you to enjoy running over 20 miles. Having done both, I can tell you it takes the same level of dedication. Who is it that says our sport needs to be huge anyway? I would rather breed a generation of wrestlers who truely love the sport. Twenty years from now it will be these lovers of the sport who will introduce the sport to the next generation.