Laughter doesn't stem from nonsense. Laughter stems from discovery, the sudden realization of a truth or a lie: the things we take for granted getting explored in unexpected ways, the assumptions we make getting questioned and recontextualized.— William Bibbiani (@WilliamBibbiani) April 26, 2019
Humor is sanity, not insanity.
As he himself notes, he is only looking at the basics. There are lots of other facets you could look at. For instance, SNL is notorious for flabby sketches -- its sketches tend to drag on a bit, longer than the humor requires -- but the Cowbell skit is one of the few examples where this comedic drawling doesn't hurt the humor, because it's not just one joke after another, but has the layering that Bibbiani notes, which means that people want to see where it's going.
In any case, the skit itself, which never grows old: