Having chanced upon this amusing discussion, I began to wonder what indeed was the point of guitar solos in rock songs?
There was a time in the early 70s when only hardened hairy bloke geeks could possibly enjoy the interminable live solo sections, whether guitar, bass, drums or keyboards. In fact there were so many transgressors in those dark days that it would be totally unfair of me to name Rick Wakeman alone. They would all (perhaps unwittingly) bore the fans senseless with interminable slots of indulgence. Punk's reaction to this culture of self-indulgence was refreshing - guitar solos reduced to a few seconds long, and usually just one or two notes (despite an enduring recollection in 79 of that pitiful band The Police doing a 15 minute version of Roxanne).
My own theory is that a guitar solo in mainstream music fulfils a different kind of role to the one commonly perceived as an aspect of the dynamic, melodic and harmonic structure of a song. I see it as an example of a demonstration skill: in other words, a way of showing off your main potential through a minor technical showcase.
For instance, walking on water is a fairly pointless action, yet it demonstrates to an audience in need of say, salvation, that by implication there must be so much more to offer. Of course, in this same way, demonstration skills are extremely effective ways of influencing, impressing, and persuading in all sorts of scenarios, not just in music.
A long-time friend of mine, Alan, a talented graphic designer, once had a prospective client in his office witness him quickly finishing off some Photoshop work. Without ever touching the mouse, Alan's fingers in a Paganini-like blur of shortcuts and keypresses, would resize, open, close windows on the screen, apply filters and conversions, and magically make paper disgorge from the printer. And understandably, this awestruck customer was convinced (quite rightly) that this guy must be the man for the job - but interestingly, without ever seeing his work.
To me, guitar solos have much the same effect, in much the same way as do Bach's flamboyant free-form preludes to fugues, they give enjoyment to the listeners who feel comfortable in the knowledge that the performers are talented, thereby adding credibility to the music; and as long as they don't start to fall in love with the belief that their solos are an end in themselves, they are a worthwhile component to a traditional song. I bet you didn't expect to hear me say that.