I guess it really depends on how you're looking at it. As purely a guitar to be played and enjoyed as an instrument / tool, then personally I would say not at all. However, people often buy vintage guitars for many other reasons than as simply an instrument: sentimentality, as a piece of history, perception of 'mojo' (whatever the fuck that is), even bragging rights. These are much more intangiable motivations which makes an instrument worth as much as someone is willing to pay for it.
I've played plenty of modern guitars that sound and feel as good as their vintage equivalents. I should also say that all of the vintage kit I've had a) it sounded and played wonderfully, and b) I scored it for a beyond reasonable price.