I read years ago that one difference between British and American humor is that the former relies on an entire humorous situation while the latter is always setting up for a final punchline. I attribute that to Jewish humor, far more common in the US, which is very punchline-driven. What little I know of 19th and early 20thC American humor suggests that is was also situation-driven driven. Black humor tends to the situational direction, perhaps retaining more of the older American style. I found the British-American distinction to be reliably true of older comedians and acts, but the two have grown back together a bit over the years.
Monty Python was legendary, yet many of their bits run out of steam toward the end. The British style may improve on repeated viewings better than the American style.