1) Satriani isn't metal. No. He isn't.
2) Where are you getting statements that metal is targetted mainly to 14-15 year olds?
3) For ever segovia there are 500 Britney Spears. Yes, it is the same argument. 95% (at least) in any genre is crap, so the fact that there are more bad metal bands than good ones doesn't change the potential for the medium.
4) I don't know anyone who considers the Kinks metal. For one thing, there are only 3 or 4 of their songs than even come close, and they, as I said, only come close. Sure, the shredding of "You Really Got Me" is an influence later down the line, but more on punk than metal.
5) Your "when I think of metal" is a really bad road to go down. The average person would say "When I think of D&D I think of socially incapable dorks." They won't even understand other role playing unless you make the D&D comparison. Or "when I think of science fiction I think of nerds and ridiculous premises and crappy writing." Again, yeah, in 95% of the cases, sci fi is bad. But the same is true of romance, westerns, spy novels, crime fiction, and anything else. That doesn't mean ALL sf is bad, or that sf itself is bad.
edit: I thought about this, and by the terms EUOL and I talked about, yes, Satriani is metal. He's done a few songs that are definitely metal. However, most of his songs are not metal.