So in theory an adhesive that did not store energy . . .

If you find one, be sure to let me know. I work for a company that builds instruments (not guitars). I'm not sure it would help, though. Plywood is almost always made of thin pieces of wood with the grain direction different on the different plies. It just won't vibrate as freely as a single piece of solid wood. Also, as noted previously, plywood instruments will always sound like they do when they are new, whereas solid wood instruments will develop more richness and clarity over the years. Plywood is very stable, and a plywood guitar won't be as susceptible to environmental changes, but it will never sound as good.

It's also true that the more solid wood a guitar has, the greater resonance it will produce. A guitar with plywood back and sides but a solid top will sound better than an all plywood instrument. Solid wood back and sides and a solid top is better still.