I've wondered this as well. Been in the same spot in the Outer Sunset since 2009. Landlord just put the property up for sale about 9 months ago. There was a lot of interest at first, even had one guy come by and immediately ask the realtor: "So how much can I raise the rent?". Thank goodness for living in a rent-controlled house.
The price of housing has definitely gone up over the years, but there are still exceptions. The city has changed, but I've also gotten older. When the downtown library wasn't skate stopped that was a hub for heated sessions at night. Now that night sesh spot doesn't exist so much. You've got the Island, but it's not the same. Soma park is its own beast, but it's a park.
As previously mentioned in this thread, the geography of the city is what attracts most people and it's damn near impossible to skate stop that.