Setting music into genres is one of the worst things that have happened to music.
I can like a rock song as well as a jazz or a classical piece. Genres often just tell you which instruments are used, which sounds and effects are used and maybe if there are singers or not (With exceptions of course). This is stupid. If you happen to like a piano piece, and someone were to play the exact same on a guitar with distortion, you would still like it. You might, however, prefer the piano version (since you might prefer the piano sound), but you would still like it. If you wouldn't like it, then nothing would make sense. You wouldn't like the tones used nor the rhythm they were used in, and then the only factor left would be the piano sound, thusly you would like everything on piano, whether it'd make sense or not.
Ultimately genres are redundant. Genres will NEVER tell if I like a song or not. However, I happen to like alternative rock/metal, but I see that as a coincidence, as it happens that there are more rock/metal musicians that use the tones and rhythms I like.
Jazz is more like freestyling. The songs are not set up by chorus and verse, it's usually just one long freestyle. People tend not to like this, since some seek structure in music. You COULD freestyle on Rock, but you'd probably end up with a form eventually, or it would just be called heavy Jazz or something.
So, Jazz as a genre is somewhat pointless in my opinion. I could like a jazz piece, and have it set up in structure, like chorus' and verses, and like it just as much.
Jazz, like any other genres evolve. From the little over a hundred years it has been active, it has changed into more than 20 different Jazz styles.
The popularity might have fallen a bit, since it isn't 'new' anymore, but it is likely that what you feel as less activity, is the evolution of Jazz. Consider it like energy, I doesn't go away, it just changes form. Okay sorry... Facepalm...
Anyways, I find genres redundant, so I don't care really. Call it music and leave it at that. Or rather just use genres differently, something that really defines the content.
kthxbye
