I doubt any one can give you an argument that would change your mind, and I personally don't care whether you change your mind or not, if you can't hear it yourself then that's cool with me. Stupefying, but cool. If you are serious about not getting it, I invite you to learn some of his basslines, and get honest feedback from experienced bass players on how you did. You can learn something "paint by numbers" and completely miss the nuance of timing and dynamics though, so even if you get your fingers in the right places at more or less the right times, don't get cocky. Craftsmanship is in the framework, artistry is in the details and the overall picture.
Jaco simultaneously played the traditional role of the bass, that is providing rhythmic weight to the harmony, as well as playing melody. Birdland is a good example of this. This was groundbreaking for many bass players, who in Jazz typically played walking quarter note lines with occasional improvised heads, or to rock players who although had McCartney, Entwhistle, Jones, etc for inspiration with the "rhythmic weight to the harmony" role, really had no one but guitar players like Hendrix and Clapton to emulate or follow, so typically just stood back "in their place" beside the high hat. Jaco shows how bass can be integral to the melody as well as the rhythm and the harmony. He also has some damned tasty grooves, for example "Barbary Coast" and "The Chicken". His timing is perfect, his sense of phrasing is saucy and audacious, his tone disregards the generations of upright players without disrespecting them. You can tell he is hearing the entire arrangement when he is playing and he always, *always* served the groove as well as the harmony.