Sleazier sounds: electric guitar solos are descended from saxophone solos

>But the truth is that electric guitar solos are directly descended from saxophone solos via Charlie Christian, who defined his instrument (which was once seen as a joke among jazz musicians, much as the saxophone’s a joke in rock) by being the first guitarist good enough to cop saxophone riffs in cutting contests

I've listened to a lot of Charlie Christian and Wes Montgomery over the years. The similarities to great horn players is quite up front, I believe.

One thing that could be of interest, if one were to actually write a book on the subject, would be tracing the cost & technology & 'market forces' between guitars and horns (sax) during the past 50 years - as in, if guitars got cheaper and better (amps, effects, etc), and saxophones kept a higher barrier of entry cost, that might be a factor in the transition. Also public perception. Like the hits Guitar Hero and Rock Band - I'm pretty sure there's no way to plug in an Akai EWI or Yamaha piece to jam out on, just because there's not really a market I suppose.

Kind-of. Thing is, "country and western" as a genre can itself be seen as "one half traditional folk, one half jazz." The "father of country music," Jimmie Rodgers, was a vaudeville performer/hobo who knew the traditional songs from the railroad workers, but who aspired to be a jazz performer. The result was a fusion of "hillbilly music" and jazz. He even worked with Louie Armstrong in 1930: https://www.youtube.com/watch?v=9BFbY9Vw8DM

Western Swing would spring up a few years later, which is clearly part-jazz just looking at its name, and would remain popular through the 1940s. This was the "country and western" that Elvis was listening to. If you check out some of the tracks from the 40s, the electric guitar solos are eerily pre-rock-and-roll, see 2:05 in this recording from around 1946: https://www.youtube.com/watch?v=aChNp0ePdMg

I think one big thing is the versatility of the electric guitar's sound. You can put it through different effects pedals to completely change the sound of the instrument. Wind instruments couldn't do this until the invention of the Varitone, but even then the natural tone of the instrument is still predominant. This is probably also why synthesizers became really popular.

I think another big factor is that the guitar (and other rock band instruments) is more "democratic". The guitar is more amenable to self-learning. It's cheaper than a wind instrument. Even beginner saxophones are several hundred USD, whereas you can get a low-end electric guitar for pretty cheap. It's easier to make a good sound right off the bat. Just press down a fret and pluck. No need to practice an embouchure and blowing technique. Really, the only hard part is to practice contorting your fingers into different chord positions. But rock musicians generally play a few simple chords, so this isn't that big a deal. And plus, you don't even have to learn to read music, since you can rely on tabs, which show you exactly how to position your fingers on the fretboard.

Bob Wills (damn, that pedal steel...): https://www.youtube.com/watch?v=ZFef08YZ6qk

Chuck Berry: https://www.youtube.com/watch?v=8RAfxiyMKAk

Wikipedia cites Wills' 1938 recording as the source, but it's fun to have the video. I totally believe Berry referenced Bill Monroe, I mean, Elvis' Blue Moon of Kentucky is a direct cover of a Bill Monroe tune. It's also thought that Scotty Moore's guitar style on Elvis' early singles was influenced heavily by Merle Travis' playing style ("Travis Picking" also see https://www.youtube.com/watch?v=N8vOTKMqzw4).