The Oatmeal has been a source of entertainment over the past few years, yes. Terrible art, simplistic jokes, and lots of really, really bad language. However its strength has been that it, for the most part, is about things that its audience can relate to.
The Oatmeal's latest offering has been an ode to his Tesla Model S.
When he's going on at length about how great a luxury car most of us will never be able to afford is, if he hasn't jumped the shark, he's at least letting us know he knows it is there.
Writers write best when they write what they know. This can become popular when it speaks to people, because they can relate to what is written. However when an author becomes successful and then starts writing about the trappings of his success -- this is where much of the audience can fall off the bandwagon.
(I've seen this theory applied to rap music. Gangster ghetto rappers rap about the mean streets and their audience in the mean streets relates. Then the next album comes out and the rappers are rapping about their mansions and cars and problems with their record producers, and the audience -- still in the mean streets -- isn't interested.)
Personally I've got nothing against him owning a luxury car.
I just don't need it rubbed in my face.