I don't know about tourists per capita but they're certainly significantly larger cities so most individual events don't cause the huge spike in hotel prices that something like an Oracle or a Salesforce show causes in San Francisco. That said, San Francisco is pretty expensive these days even if there isn't a huge show on just because of overall demand.

In general, public transportation in San Francisco isn't very good although it's really not very good to get to the Javits in New York either. However, the Fisherman's Wharf area and Nob Hill aside aside I'm not sure there's a huge amount of hotel capacity in San Francisco outside of a 10-15 minute walk to the convention center anyway.