Although I’d never even attempt to put these kinds of things into percentages, I will risk angering other armchair experts and say that the notion that wood has nothing to do with tone is patently false. In my opinion. But it’s true. Please don’t scream at me.
I mean, pickups are just sensors ‘picking up’ the vibrating string, and the string is resonating along with the neck and body in tandem to create the string note tone the magnetic field of the pickup is perceiving. Everything from wood to the type of metal used in the bridge, to fretboard material can have a distinct effect on the overall tone of a guitar. For instance, most people associate a mahogany-bodied guitar with deeper tones, maple with sharp pick attack and bright sustain. This plays out with
And yes, pickups also sense the vibration of whatever body they’re installed into. If you took the same pickups, strings, and electronics and mounted them all to a piece of aluminum, damn right they’ll sound different than mounted to a nice piece of wood. Now, the pickups aren’t only sensing the vibration of the body, but it is most certainly a factor in tone, as the vibration of the body feeds into the mounting tabs on the pickup, etc. It’s all connected.
Everything, and I mean everything that comes into contact with the string’s vibrational length (including magnetic fields) has an effect on the overall sound and response of a guitar. That’s why changing from steel to titanium to plastic saddles will drastically change the sound of a guitar, and why certain pickups can enhance the sound of an existing guitar. People get blue in the face arguing the merits of set neck, neck thru, and bolt-on construction and how each can impact the sound of an instrument.
When I go guitar shopping, the first thing I’ll do is play a guitar unplugged. If that guitar has a pleasing acoustic sound (yes, I’m talking about solidbody electrics) then the likelihood of it also having a fantastic electric tone is nearly guaranteed. Ever play an electric guitar that just sounds dead? Chances are it sounds the same way unplugged. Bad wood means a bad guitar; you can make it sound better with decent pickups, but it’ll never sound great.