True it is that humans, being primates (as well as souls, but that is a another matter) interact socially with one another using myriad visual cues---the regal alpha baboon looking serenely at the horizon as he is groomed by his adoring mate and respected by his troop (for the moment) no doubt is confident that everything is as it should be (and that is possibly why they have not developed television or other characteristics of an advanced civilization, grin). My observations here are not entirely sour grapes as it were, i.e., there have always been those who admired me on substance as well as appearance (perhaps a select group, grin). I am complaining more about what seems to me to have been a transformation of culture after about 1974 such that appearance of things began to triumph over substance to a degree not previously seen. This may be partly the natural outcome of the rejection of values that occurred in the 60's, leaving in its wake only the herd and its collective narcissism.
I watched a 2010 documentary where some new jack groups played at Abbey Road studios. One of the band members (a guitarist and vocalist) explicitly stated the new philosophy: "I don't play all that well, nor do I wish to, since that would constrain my creativity" (paraphrasing). This may be less true in current country than popular music (I can't even call it rock at this point), since you do have the country session guys making it into the bands, providing the technical talent to buttress the "talent" (the studio term for the vocalist that is selling the song to the purchasing public).
I don’t believe that "good" is a matter of popular vote though. If you define good in terms of sales then you are talking more about successful rather than a gauge by competent practitioners of the range and depth of capability and creativity an individual brings to the table with his instrument, voice, composition.
As far as the hypothetical battle between "old rockers" and current professional country players, this would be difficult to quantify, e.g., in my opinion there aren't any country players who could keep up with Jimmy Page or Steve Howe (and no one can keep up with Al Di Meola, but that is a matter of superhuman capability), but Billy Gibbons, or Eric Clapton or Mark Knopfler would be easy enough to follow note for note for any lead guitarist, whatever the genre. It is important to note that reproducing licks does not necessarily mean that they could be independently created. It is foolish to sneer at a guitarist simply because you find it easy to play what they play---the genius comes what notes you play, not how they are played.
The popularity of rap does not affect my understanding of how you properly rate the technical virtuosity of a musician, or my own personal reaction to this genre or any other (if I walk the road less travelled, still it is my own road). The popularity of rap is merely an indication that tribal reinforcement is still a purpose of music, loosely defined (normally I would consider music to require both rhythm and melody, but I am biased by my culture I suppose), i.e., rap tells the story of boys in the hood and thereby imparts some significance that would not otherwise be there (there have always been rougher parts of town, but few sang of it---Elvis was a bit sentimental in his take of the ghetto, grin).
The perception of art is highly subjective. Anything humans think about or experience is conditioned by their own life's experience and personality. This is true even in areas like science, where we purport to produce explanations that stand up to test by others, test by reason and possibly experiment. I say purport because when it comes down to fundamental beliefs, even professional scientists can be myopic. For example, the scientific community was outraged that a study (Feeling the Future...) which establishes that humans may at times sense future events before they happen was published in the Journal of Personality and Social Psychology. The current scientific establishment believes (with religious fervor, ironically) that "the brain is just a computer made of meat" and that "we are all zombies; nobody is conscious." Any scientist who challenges those assumptions is attacked out of hand---because of the irrational bias of the scientific community on this subject. I do believe, however, that if we work at it, we can at least be aware of our biases---and the influence of the ego, which, for obviously good reasons in terms of survival, "may need to impress, dominate or control and sees others as either threats or tools."