Erm.

What does my derailleur do for me when I realize that the corner at the bottom of a steep descent is sharper than I thought?

I usually put on my brakes and don't shift for it.

And I don't buy that trek doesn't charge more for their bikes because of the trek name - because trek does. Seven charges more for their titanium bicycles than litespeed does for similarly speccd bikes. Trek charges more than jamis for similarly speccd bikes. Pinarello charges more than whatever. Sometimes it depends on the number of bikes being produced and the market, but differences in prices are not purely higher prices = better bike quality. Just as a chanel purse is not 1,000 times higher quality than a regular leather purse.