An answer to the question: "Anybody else ever get totally fed up with their sound? What do you do about it?"
The short answer is "keep searching."
Over time, you'll develop a feel what works for you, and why. Meanwhile, buy gear assuming that won't keep it. Buy used gear at or below market value and you won't take much of a hit on the resale. Think of any loss on the sale as "rent". Pay attention to recommendations, but be your own judge and jury - we're talking about your sound, not a popularity contest.
Everything matters. String guages, picks, woods, pickups, scale length, construction, amps, speakers, ... The list is nearly endless. If you try something different and hear a change that you like, figure out why that works for you - perhaps there's a general principle to be learned. Don't approach it the other way: "This is supposed to be better because (insert marketing hype or conventional wisdom here)... Can I hear/feel/appreciate the difference?" Guitarists are notoriously effective at kidding themselves about things that really don't matter...
And technique is at least as important as gear. Don't forget to keep woodshedding.