Meh. Chicago beats San Francisco tourism numbers both in number of visitors and in overall tourism revenue, and while I will forever love Chicago foremost among all US cities, one place where I think we can clearly concede an advantage to SF over Chicago is tourism --- the SF sights, the ocean, the woods to the north, the nearby mountains, Silicon Valley, the Chinese culture, the history of the region. Chicago is practically the apotheosis of "going to see X, Y, and Z which happen to be in Chicago", and it does fine.
It seems that a large fraction (most?) of the tech people picked their cities largely because that is where their job is.
People who oppose major changes to the character of their neighborhoods and cities aren't all just worried about the resale value of their house. They often are more motivated by a desire to preserve those features of the area that attracted them in the first place.
Also, I think a lot of tech people forget that there are other sectors that also provide a lot of jobs and bring a lot of money to the local economy. For instance, tourism and hospitality provide a very large number of jobs in San Francisco, and bring in a lot of outside money.
Change the look and feel of San Francisco too much and you could reduce the appeal to tourists. You risk changing it from people thinking of it as going to San Francisco and while there visiting attraction X, Y, and Z to people thinking of it as going to see X, Y, and Z which happen to be in San Francisco. A city will do a lot better with tourism when the city itself is thought of as a major attraction.