Chuck Nevius is big into gentrification these days. He thinks it's a dandy thing and "no longer a dirty word,"  says the even longtime residents of the Mission love it, and has a nice photo of a person walking in Dogpatch, where two really cool dive bars just shut down -- thanks to the gentrication that's such a great thing.
Nevius quotes Randy Shaw, who has a bizarre statement:
In the '70s and '80s there was massive displacement of residents in the Haight, Noe Valley and the Castro," says Randy Shaw, executive director of the Tenderloin Housing Clinic. "But now you are seeing a massive influx of upper-income people into previously unoccupied areas."
What? "Previously unoccupied?" Like the Mission and Soma and Dogpatch? Unoccupied by the wealthy, maybe, but there are people living in almost every square inch of San Francisco, and in some parts of town, they are low-income people, and richer people force them out. That's happening on the same scale today that it did in the 1980s, except worse: In the 80s, if you werer priced out of the Haight or Noe Valley or the Castro you could move to the Western Addition or the Mission or Soma. Now prices are so high everywhere in town that your only move is out of San Francisco altogether .
And while ol' Chuck does admit there are downsides, he seems to think that somehow you can move wealthier people and more upscale establishments into existing lower-income areas without anything bad happening, as long as you respect "the delicate balancing act." 
But it isn't a balancing act at all -- it's a zero-sum game. There's finite space in this city, and when when something or someone comes in, something or someone has to leave. (Yes, you could build a lot more housing, but nobody's building housing for working-class people.) But you can't build more storefronts on Valencia or Mission; force out the existing community serving businesses and they have noplace else to go.
San Francisco has failed spectacularly at the fundamental challenge facing a city under this kind of pressure. First, before you allow more development, more upscaling, more of what C.W. Nevius loves, you have to protect existing vulnerable populations. That's not a balancing act; that's a mandate. If you don't do it, you lose the character of the city and San Francisco becomes another sterile, corporate community.
Jesus. Why is this so hard to understand? I've lived through it several times, these booms that people like Mayor Lee and Nevius always celebrate, and every time, the pattern has been the same, the city has been damaged, and community institutions have been lost. I'm not one of those preservationists opposed to all change, but again: First protect existing vulnerable populations.