This time around, there is an established norm for how the startup scene works, and that scene requires MBAs and business suits. The people who have come around to take advantage this time are not nerds, they're not tech people, they're people of all sorts. I think the best way to so describe them is to say that these are normal people. That's fine anywhere else, but not in SF, home of the weirdos.
SF has NEVER been a town of normal people. This gentrification process is basically turning SF into the Valley. The old days where burning man types held parties in their warehouses are long gone now. The first dot com boom made millionaires out of some of these weirdos, like JWZ. But this boom is not doing that. The people getting rich now came to SF just to get rich, and they have no interest in being weird, burning man, or any of the SF-style weirdness.
Yes, in 1999 artists had to leave SF. But at that time, it was just some artists and weirdos leaving. This time, it's ALL of them leaving. There are no more blue collar people in SF. No more weirdos in SF. No more poets in SF. It's a real shame, and while it could have happened in 1999, it didn't quite get going enough to really do the damage that's being done this time around.