What do you mean, how can he improve? Dave isn't exactly the most round musician in the world; I'd love to hear some Gilmour-Jazz on a Hollowbody Gretsch, but will I? No, because he didn't take the time to really learn jazz. There's no excuse for Dave not getting better from '73 on; I'll tell you what I think of it; Dave was afraid that if he started getting more influences, that people wouldn't like his lead guitar playing (the change), and that he'd burn out. He sounds exactly the same, if not worse right now, compared to Dark Side of the Moon. His solos are shorter, and now have less of a sparkle than they once did.

A top-5 Guitarist has to continue to innovate; Hendrix did so during his short career, but comparing Hendrix to Gilmour doesn't do either justice; not because of talent level or anything, but because of the fact that Hendrix had an extremely short career, and Gilmour is still around. Hendrix didn't have the chance to show innovation through time, Gilmour did, and Gilmour failed. Would Hendrix do the SOS for the next thirty years, like Gilmour? Who knows.

About my non-guitar playing theory, that's only a supplement; Those were things that you can do while you are away from the guitar for a few hours that can boost you up quite a bit. There's a huge difference between that, and simply not playing much anymore because you are now making mega $cash$.