"There's a horse loose in a hospital": Is John Mulaney a comedic genius?

Could a stand-up routine ever rise to the level of "art" — the kind of performance that rewards multiple viewings, whose humour grows and deepens, which contains subtleties waiting to be discovered? Enter US comedian John Mulaney with a 2017 comedy sketch. There is something undeniably enduring, timeless even about Mulaney's act.