I think he nails it there. I think a lot of times people neglect the total package. I really dont care what a gutiar or effect sounds like in guitar center. I really care about what its going to sound like when i get it in my rig. Also how it fit in the live and recording mix with the rest of my band.
I think a lot of people who cant hear the difference are using pickups/amps/effects that make it all sound the same. One of the reasons I didnt like my modeling amp my les paul,rg, parker, and strat all sounded pretty much the same. Not so with the mesa.
On acousitcs the top is your speaker and the rest your cabinet, so there is a difference there. But its again a total package, braces, strings, string mounting, finish etc... Remember a lot of the older martins that are supposed to be cool people scalloped the inner braces. Put heavy strings on your acoustic and tell me it doesnt sound different. Heck tryit on an electric too.