Funny you posted this today, as I wonder about this issue of braces being always necessary, too. In my area, almost no child escapes childhood without braces. It is <b>NEVER</b> questioned here - every child gets years of othodonics, it is expected and accepted. Most start getting treatments at age 7. I know first graders in braces. I swear, every kid has something in their mouths by third grade, whether braces, retainers, or the ever-growing-more-popular palate expander. More and more kids are getting braces twice, like another poster said.
I think (here in my affluent area) the attitude is that if you don't get years of orthodontic work for your children, you are a neglectful parent dooming your child to a life of disavantage.
I think also the attitude is that no matter how straight a kid's teeth come in, years of orthodontics can make the teeth look even better.
As for your son, IMHO definately get the braces, no matter what the cost. The orthodonists have won the war on this issue - everyone HAS to have straight attractive teeth, no questions asked.