There are comedians who can attract a very large audience, large enough to make them major celebrities, but that doesn't mean that aggregating preferences doesn't produce mediocre jokes.
Instead, comedians build an audience of like-minded people, and get to know that audience very well. It's a little bit like the process of finding product-market fit for startups. You can achieve great success by catering to the needs of a very large market, even if you can't cater to everyone's needs.
> It would be interesting to compare how well LLMs can estimate how funny a joke is vs how good they are at generating jokes.
Academic psychologists have not found a quantitative measure of "how funny a joke is." If there were such a measure, LLMs could try to optimize for it.
But there isn't such a measure, and, if my argument is right, there couldn't possibly be a measure like that, because jokes have to be surprising but inevitable in hindsight, and different jokes will be surprising/inevitable to different people.