Consider bottled water for a moment.
How many companies tout their product as being something along the lines of "100% pure mountain spring water", or something similarly idyllic?
Well, here's the thing, if you're starting with pure water, there's no way to make it "more" pure. It's water. Period.
Now, go price a bottle of Evian, and then go price a bottle of Sparkletts.
Both contain, well, water. Nothing more, nothing less. Yet the Evian costs three times as much for a 1.5 litre bottle.
I've got news for you: You're not paying three times as much because the water's better. You're paying three times as much for marketing, advertising, operating overhead, etc.
None of that has anything to do with the value of the water, just as a high price does not necessarily reflect only the value of an instrument.
When you buy a Taylor (or Martin or Guild or Gibson or what have you), a lot of the money you're paying isn't going to address the intrinsic value of the guitar, but to ancillary costs wholly unrelated to the guitar itself.
People buy into the marketing. People are paying for the very marketing that's convincing them to buy a guitar. With regards to the marketing aspect, it's self-sustaining. Company A tells us Product X is good, so we all run out and buy Product X, thereby generating more cash for the Marketing Department of Company A so, when Company A introduces Product Z, they can have money to spend on marketing and advertising to tell us how good Product Z is, so we'll go out and buy that.
Eastman is putting out some very nice guitars right now. They're building guitars which, if you covered the headstock, you'd mistake for Martin, Taylor or Gibson. They look like them, feel like them and sound like them. Well, Martin, Taylor and Gibson should take note, because Eastman is doing it just as well, and for a fraction of the cost.
The "big three" lean heavily on the fact that they're "American made". It's impossible to quantify that, though. Yes, there's a certain implied value in that, but I don't know that anyone's ever been able to place an actual dollar sign on it.