I own some old instruments, and I'm going to come right out and say it: there's a lot of cache' in an old instrument, because you can't just roll into a guitar center and buy it. One needs to look for an old guitar, and often times wait awhile before the right thing comes along.
Fact is, especially with electrics, age has ups and downs. Classic guitar tone was created with classic guitars, and it's harder to duplicate the sound with modern guitars than it is to just buy old ones. However, pickups lose their magnetic force, so they don't sound the same today as they did twenty years ago. Moreover, when classic guitar tone was being created, it was being created on new guitars. Most real professionals today also play new instruments, mostly because they're reliable, and replaceable should something break.
Many guitars are still handmade today, but some are mass produced. Be careful not to attribute "mass-produced" to "lower quality". Machines have far more exacting tolerances than humans, and if calibrated correctly should work wonderfully. Hand made doesn't really mean some wizened old luthier in a brown smock is painstakingly sanding and fine tuning your instrument in a dimly lit workshop with woodwork hanging from the ceiling. It usually means minimum-wage labor is lined up and performing the same repetitive task 8 hours a day, caring little for the finished product.
There are some old guitars that have been well cared for and play beautifully, and there are some new guitars that have truly been personally built by a knowledgeable luthier. In both cases, these guitars are expensive and hard to come by. New or old, you get what you pay for. If you're going to be using the instrument a lot, it's really best to go new or buy only from someone you personally know and trust.