Perhaps this is related to the very low number of hotel rooms in San Francisco -- 1/3 the number that exist in Atlanta, and 1/2 of the number in Phoenix. San Francisco makes it as hard as possible to add new inventory to this market.
San Francisco is throwing up plenty of hotels. For example, almost 200 new rooms are coming with a new 800-foot tower that has just started construction: https://www.sfexaminer.com/news/new-skyscraper-to-rise-in-ci...
There's a concerted media effort by conservative outlets to paint SF in a bad light. We have plenty of problems; plenty of self-made problems. But outsiders literally conspiring to harangue us says more about them than it does us.
Sources:
* 97,500 rooms in metro Atlanta. https://www.ajc.com/business/metro-atlanta-add-more-than-000...
* 34,000 rooms in San Francisco. https://www.sfchronicle.com/business/networth/article/Like-r...
* 8,376 sq mi in Metro Atlanta. https://en.wikipedia.org/wiki/Atlanta_metropolitan_area
I'd be interested to hear other people's experiences but it feels like most conferences in San Francisco would start to become miserable in hotel price and commuting for people coming from out of town once you start getting to 20,000 or more people.