You had me up until this bit. There are lots of incredibly musical people for whom Parker just isn't that gripping. And because melodies over chord changes aren't ones "thing" that person automatically isn't very musical (or did you mean that someone who can't recognize Parker's genius isn't that musical - but either way)? No, not buying it. It took me a long time to be able to appreciate Charlie Parker and other bebop players/composers. Does that mean I wasn't musical when I was younger, or that it suddenly became possible for me to be musical once I'd started to appreciate Parker? Harmony was never an African thing back in the day (and still isn't in a lot of of the music produced in Africa. Are you suggesting that Africans have, traditionally, not been musical?
That's a great point, thanks for making it. I guess the honest answer is that I'm not sure. In my opinion, and I'm open to being proven wrong, you did have the musicality and it just needed development. Perhaps if you were even more talented you wouldn't have needed that time to develop, but then most of us just aren't that brilliant - Herbie Hancock, Pat Methany, Ray Brown, Ella Fitzgerald, Billy Holliday, but we're talented enough to get there over time. Some folks aren't talented enough to get there, ever, in my experience.
And certainly, many musicians have different strengths - rhythm, harmony, melody, lyrics, etc, but the pinnacle of jazz requires deep abilities on all of these levels. Most other musical styles don't.
Having said that, my experience, 44 years now, since I was 8 years old, tells me that for some folks music is a compulsion, myself included, and a smaller subset of those, are musically sophisticated enough to get bop.
So, sorry for the long post, but you've encouraged me.
I'm 52. The lightbulb went off for me when I was 8 and nagged my folks into getting me my first guitar. Already, I liked music that was deeper than was on the radio, I really dug the musical opera Jesus Christ Superstar, which I would credit with significantly contributing to the prog-rock style.
What I really wanted was a Hammond organ, but I was thrilled with the guitar never the less. I started out with music lessons on guitar like many, but quickly progressed into more and more sophisticated rock - Doobie Brothers, Steely Dan - and electic fusion blues. I even did my B.B.King imitation at one point in my teens, and then I added a lot more "blue notes".
Then I found Parker and Miles Davis. At first, I didn't get what they were doing, but I was intrigued, and curious, so I dug deeper. I played my guitar through the Omnibook and sung Parker's solos as best I could and that converted me. After that, I found cats like Dexter Gordon and John Coltrane, and purists avert your eyes, Dave Holland. So, for me, sophisticated treatment of harmony coupled with a rigid rhythm floated my boat. But I'm not so musical that I got there immediately. I had to work at it. But, I was intrigued enough by what I heard to dig deeper. Certainly there are other ways to go, but for a person who's all in their ears, that seems to be the way to go. Note that some classical music broke the path here, particularly Beethoven and later 20th Century composers.
I've played with a lot of bandmates who stopped at the harmonies of the Rolling Stones - not even the Beatles - or who solo like a wanna-be B.B. King, or who love Broadway musical numbers like "Polkadots and Moonbeams". And, I think they're limited. The B.B, Kinger's know only ONE scale REALLY REALLY well. The broadway folks play everything very consonantly. Blue notes have to be "prescribed". I don't think those folks have the musical talent or maybe it's their personality, to "get" the more complex harmony of Coltrane, Miles, Gordon, or even Holliday, but maybe I'm wrong. I do know that players I've played with who tend to less harmonically complicated music disappoint me with their musicality because they seem comparatively one dimensional. I have a clear preference for the folks who are striving to evolve a new harmonic sense, even if it doesn't work out most of the time, but at least it's new, and different, and true to them, rather than channeling some obvious "scale-sound". So, is it personality or musicality or a combination of both? You tell me.
So, to answer your last two questions, if you haven't learned to appreciate Parker, I doubt your musical talent. You may be wicked at sight reading or keep time like a clock, but I think you're missing some dimensions. Are native Africans unmusical? I have to say "yes" - they're brilliant at rhythm, but music has evolved to include both rhythm and harmony and traditional African music excludes harmony to concentrate on rhythm. A final disclaimer, I realize that most jazz is rhythmically limited, or static. For jazzers, the consistent pulse is key and in that sense, it is less sophisticated than many other musical styles with a more fluid and sophisticated rhythmic sensibility.
Very last point: It's true that jazz is hard to define, so let's settle on a broad definition - jazz is a musical style descended from Louis Armstrong with relatively static rhythm and sophisticated harmony that usually includes improvisational portions. This definition includes modal jazz with only a few chords because those chords are almost always chords with a lot of extensions. It excludes Yanni and Kenny G because their music is more akin to instrumental pop.
Okay, tell me where I'm wrong. I welcome it.
P.S., Dorsey doesn't count. It was called jazz and it was very popular in its day, but it was clearly dance music, not listening music. It was the pop of its day, but not much more sophisticated than folk or rock music. I'd be willing to bet that there's folk and or rock that's more harmonically complex than Dorsey or Glen Miller.