Old Fenders likely got better wood and more personal involvement due to less automation. They have all been around long enough to have the wood age, cure, collect mojo or whatever it is that old instruments do. There is the theory that the poly finishes are just too sealed and hard to 'breath'. I buy into that...except for the effect of Fullerplast. I am pretty sure that there had to be some individual differences. Maybe Abigail was daydreaming one day and ended up with a 10% over wound pickup. Maybe Tedeo got carried away and shaped an extra thin neck. Those things can be magical. They didn't happen to every one that came out of the factory, though. They are all special in that they are old. Many are special in that they are not exactly to spec. That can be good or bad and part of that depends on who you ask and what they prefer. I will say that the newer ones are more consistant. I will also say that whether it is the very first P or a Squier built yesterday a little love and a good set up go a long way.