I think to some extent all the parts of a solidbody must sort of "settle" over time so they resonate well together.
I'm not sure how noticeable it is though. If I've been playing a fairly heavy, inert, acoustically quiet guitar and I go back to a lighter, more resonant one that I haven't used for a while, the difference is suddenly very obvious. But did the second guitar always sound like that anyway?
Then again, I have days when guitars I'm normally comfortable with suddenly seem stiff and unresponsive - I think that must all be in my hands and my mind.
The few real vintage guitars I've played have been much louder and more resonant than new ones, but I assume that's down to the timber (possibly better quality to begin with) drying out and the finish hardening. But it could be partly due to them being "played in", too.
So.... dunno really..... :?