WJGreer said:
And, according to Marcus Miller, who knew him, Jaco could not improvise.
By your own quote, this is not exactly what Marcus said. He said that "
a lot of his stuff wasn't improvised," and that "even Jaco couldn't improvise those perfect solos."
This is not saying he couldn't improvise. You can't function over any extended period in a jazz context, with jazz musicians, without being able to improvise to some extent. At least you can't if you're a rhythm section player in a small ensemble (I guess if you're third trumpet in a big band, you could get by with just playing the ink).
I don't think the term improvise has quite as narrow a meaning as you suggest, even in a jazz context, though I agree that in jazz it's very often (perhaps most often) applied to soloing. But when a pianist lays out some new chords before the head of a tune starts, he can be said to be improvising an intro. When a bassist is handed a chart of a standard with nothing but chord names and a couple of rhythm hits, he can be said to be improvising a walking bass line. A jazz bassist who doesn't take a solo all night is still an improvising musician, if he's not reading his entire part note by note.
I suspect that what Jaco meant was something more like, "You think you're bad because you can make up (good) solos on the spot."
The logical consequence of believing that Jaco couldn't improvise is to believe that he could only (a) play something he'd already composed or (2) reproduce, without alteration, something he'd already heard. Neither of which seems to fit the musician I remember hearing and seeing, or for that matter the one depicted in Milkowski's book.
Regarding the anecdote about All The Things, I'll have to check myself on this, but what I recall from the book (which I read a few weeks ago) is that he supposedly looked at the chart once, then put it away and proceed to burn the tune down. That's something that would be beyond the capacity of someone who can't improvise.