The current storyline in the Zippy the Pinhead newspaper strip has its cartoonist, Bill Griffith, lecturing Zippy on the art of cartooning. (Here's a link to a page where Griffith displays recent efforts and offers the originals for sale.) In the 9/4 strip, Griffith proclaims, "Any cartoonist who doesn't do th' final drawing for his or her comics is no cartoonist at all in my book." And in the 9/5 one, which may not be posted yet, he takes off after cartoonists who use assistants and don't even do their own lettering.
So according to Bill Griffith, Elzie Segar was no cartoonist at all. Neither were (or are) Milton Caniff, Al Capp, Jack Kirby, Will Eisner, Frank Miller, Alex Raymond, Mort Walker, Hal Foster, Floyd Gottfredson, Garry Trudeau, Dik Browne, Chester Gould, Roy Crane, Hank Ketcham, George McManus, Leonard Starr, Johnny Hart, Chic Young, Mike Peters, Harvey Kurtzman, Steve Ditko, Burne Hogarth, Neal Adams, Roy Crane and…well, you get the idea. Some of those folks did their work solo for a time, especially early on, but usually chose to employ letterers and/or assistants. Even Mort Drucker, Sergio Aragonés and Jack Davis have had others do their lettering, and Carl Barks sometimes had his wife inking backgrounds and doing lettering.
In one panel, Griffith asks, "Did an assistant drip the paint for Jackson Pollack?" Apparently not, but Rembrandt, Rubens and Michelangelo had help with some rather acclaimed work. I guess Rembrandt was no painter at all.
Actually, I think it's great when a cartoonist does his or her work without help if they're able. Some aren't, especially some of the folks who did daily strips back in the day when they involved a lot more labor than a strip like Griffith's does today. Some aren't very good at lettering and/or figure that the time they save by having someone else letter or ink backgrounds is time they can put into writing or the main drawing. Some simply find that they don't work well in isolation and that working with someone else spurs their creativity. Milton Caniff needed a letterer because he was left-handed and if he lettered his strip himself, he was always smudging the wet ink.
Griffith's sentiments cause me to wonder if he is aware how many great cartoonists haven't done it all alone, or if he really thinks none of those men produced good comic art.