That's a ridiculous statement.
As a musician i started on bass, almost 20 years ago now. When i was in high school i joined the school band, and the music teacher was a huge motown fan. Well we played alot of motown covers, and i had to learn all the bass lines. Basically we would play the motown stuff with the teacher, and whenever he would go out for a smoke, we would jam rock and metal stuff.
Both styles take technical skill, musicianship, and composition skills, in this thread, it's all a matter of preference.
Have to agree wirh Speed55 there Hajo.
Your criteria is kinda wide. If you mean who can play the most 64th notes in 60 seconds maybe that Jamerson dude might do.
As far as an all around musician some in contention might be: Jeff Berlin, Stanley Clarke, Bootsy Collins, Lance Hoppin, John Paul Jones and Marcus Miller.
The problem is the deeper you look, the more good\great bass players you can find. Who is to judge?
Slade 
I left the criteria wide-open on purpose so I'd get a larger response. I'f I'd specified a narrower criteria, like who's the best jazz bassist, a lot of people wouldn't bother responding at all.
I believe to better appreciate Jamerson, it helps to understand the way that Motown created it's music back then. To a large degree, the percussion and bass parts were often ad lib'd, much like live jazz. Jamerson's real talent wasn't just that he could play, he to a large degree "created" many of those old classics. One of the reasons he's developed a following in recent years is largely sentimental. Sadly, it took 40 years for the guy to get any recognition. As a studio musician, he might make $150 for recording a song that would make the vocalist(s) very rich. The poor guy died young and broke, and felt understandably betrayed.
But we all have our own preferences.
(as far as that machine gun 64th notes delivery, I don't know how in the Hell the guy did it. The guy only used one finger!)
