I think it has something to do with engineers going "Hey, lets try this!" and then they say "its better!" and then its not better, but since they've put all that hard work into it they just try their best to convince themselves. At least that would be my Dad's answer. He hates MBAs, because he thinks that they have no common sense anymore.
Another thing is that the quality in materials has gone down so that its cheaper to make things (screws, wire, copper, components etc.)
There's also just... something.... about having a vintage model. Chances are that someone else used it, and maybe someone before that. Who knows that kind of musician they were? Its the magic of other musicians playing this awesome old thing, and now its in your hands and you can channel that magic through your fingers... or something like that... I gotta lay off the beer.