Good question, I suppose I have to find the best way to answer this.
I do see the two as being distinctly different. I never considered Jim Schultz, Jim Davis, or Gary Larson to be 'artists', because they only drew doodles, really. What they, and Kurtz did/do is focus on proportion, form and structure in 2 dimensions only. You don't see Garfield from behind, or in profile, or from a top-view... it's always the exact same 3/4 view, sometimes a straight-on view just to mix it up. That's not art, that's perfecting one single way of drawing one single character, from the same perspective/distance, constantly.
A Cartoonist, when asked to draw a landscape, could probably do it... when asked to paint a landscape may not be able to, when asked to work in chalks/charcoals, or to work with clay or metal... probably wouldn't be very adept at it. This will change from person to person of course, but that's the gist of how I see it.
An artist will be able to sit down and paint, draw in pencil & ink, use chalk & charcoal, create dynamic settings, draw from all manner of perspectives/distances, and create so many different KINDS of work (interpretive, abstract, realist, etc). They'll employ various techniques showing depth, shading, contouring, etc. Cartoonists, like kurtz, don't (or can't) do any of that.
On the topic of Kurtz, some people say that his sketches prove him as an artist. I've yet to see a single sketch he's done where the character he is drawing is not in 3/4 perspective. Even in his random doodles, he limits himself to that single perspective, which - to me - means he is lacking the ability to do anything else.
The work of a typical cartoonist:
Note: other than Garfield in the 3rd comic panel, every single thing is drawn in 3/4 perspective.
Work of a 'cartoonist' who OBVIOUSLY has artistic background:
Note: See how the artist (Ian McConville) plays with perspective, range, depth and colour in order to give everything an organic feel. There isn't even a reliance on ink outlining, it is all digitally 'painted'. This comic shows INCREDIBLE depth, and this guy puts out one of these a week, on average, while in school, and presumably working a part-time job. To me, that means he'd be able to do this daily if it was the only responsibility he had (like Kurtz).
Do you see why I have a distinction between cartoonists and artists?
Of course, there are some 'cartoonists' who are probably fantastically accomplished artists. If you look to 'Ctrl-Atl-Del-Online' you'll see every single comic employs the 3/4 perspective. However, when you visit his sketch pages, you see that he obviously has a much stronger grasp on drawing than is shown in his comic. Kurtz's sketch pages do not show any greater understanding of depth, or perspective.
Make some sense?
