I hope I don't come across as too hostile either, that is not what I mean to do.

What I am trying to do is tell people how I have had successes and failyers and that thinking in things in terms shades of grey is often more useful than simply seeing everything in terms of black and white.

Also remember that people like my self who having been playing for 20+ years can get set in their ways, and that does occasionally make me crabby (yes I am that old git!).

Anyway, in answer to your post.... Yes ! Because theory is vast and covers many different things.

Examples being: how to construct a chord, which chords go together and sound a certain way, how scales are constructed, and how they work with chord progressions.

So, to play a really nice sounding solo doesn't require a vast amount of theoretical knowledge, but it dose require some to know a) which chords are being played by the rest of the band, b) which notes or scales to play over the top of the chords everyone else is playing.

No need to write a thesis on the modal structure but It helps to know what a pentatonic scale is !!