Apparently an analysis was done in restaurant menu items and gentrification is making it worse because cooks don’t make enough to live close to work, so there are fewer skilled ones and hence fewer items and more salads :)

The weather is a close second, I'm in Noe Valley which is really chilly and I like that. You should have people at your place and cook for them and call it a party, San Francisco has The Midway, Great Northern and outdoor activities at Golden Gate which are kinda "world class" partying but there's a lot going on in house parties and places of ill repute.