Yep there are some parents who are nuts and they are the sole reason that their kids quit the sport. The other reason is the woosification of kids and society as a whole. Wrestling is a tough sport and many kids will just go choose to play video games or easier sports such as soccer, baseball, or basketball. These sports do require skill, but not near as tough, mentally or physically, as a combat sport such as wrestling.
I will never forget a Physical Education class in college in which the entire class did a pacer run competition. Many of the students dropped out early on and at the end it was a basketball player, who started on the team that won the national championship that year and myself, an average former out of shape High School wrestler. When things got tough he eventually quit, I was not going to quit no matter how hard it was going to get. Wrestlers learn this and it becomes second nature. These other sports simply do not make a person near as tough mentally or physically.
Wrestlers learn this kind of work ethic that can be applied to life. I think if we focus on these kinds of benefits with wrestling, then we can get parent by in and possible grow the sport in the future.