I'm glad that you've done very well, but you do recognize, of course, that you're an exception to the rule. The majority of high-school diploma only workers don't come close to what you're describing.
Actually, I think it's more common than a lot of people think. None of my immediate co-workers (who make the same as I do, or more in my boss's case) have degrees, neither do most of my DH's co-workers, who also makes around what he does. I have a friend that works in the same field as I do and while she does make less (her company doesn't pay as well, unfortunatly) she still makes good money and has decent bennifits.
According to our friends at Wiki, as of 2005 about 85% of US adults have a HS diploma and about 28% of those have a Bachelors. So that's a lot of people that don't have a 4 year degree in this country.
Now, I'll never argue that having a degree most certainly increases you earning potential over your working lifetime, the stats don't lie about that either. But just because a person with a degree earns more over their working career vs. someone who doesn't, it also doesn't mean that the person that earned less as a result of not having that college ticket punched lived in poverty, or even among the lower classes.
I don't have kids, but if/when I do, I'll certainly hope they go to college and will encourage them to do it, even if they want a trade I'd love to see my kid(s) with a business degree so they can run their own construction or plubing business once they have the nessesary experiance in the trades (or restaurants or auto shops, or whatever). I think that having a college education is better than not having one. But not everyone is college material, as other's have stated. My DH is one of the smartest people I know, but he'd do misserable in school because he's just not built for it.
I guess my point is while having a college degree is a great thing (and children should be encouraged to go that route if they are the type that would do well in college), having only a HS diploma isn't the end of the world either. A lot depends on the individual in question and how hard they are willing to work and how carefully they choose their field, but really, isn't that true of everyone, regardless of education?