There's a difference between "the middle class leaves" (because middle-class jobs are gutted) and "the middle class is forced out of their homes by the upper-middle-class."
There's only so much San Francisco to go around. Why should the people who got there first have a right to it? We pretty much destroyed that precedent when we founded this nation on top of the natives' ground. In fact, if we follow American historical precedent, those people should not only be forced out of their homes, but also murdered, raped, etc.
Perhaps you don't believe anyone should be allowed to settle down and work and live in a small but reasonably comfortable home if they can't pull a six-figure salary
The issue is whether they should be able to live anywhere they want. The truth is that if the value of your home increases to the point that you can't afford to pay the property taxes, you can afford to sell your home and move someplace else. People are always complaining about civilization arriving where they live. Here's a nice example. There's some folks on our road who have been here apparently since before it was paved. One day I evaporated one of their chickens with the Astro because they couldn't keep them under control and they were out on the road. One of them decided to dart under the van as I was passing by it and the rest (and the chicken) is history involving a gigantic expanding spherical cloud of feathers behind the van. Their response was not to improve their coop, but to spray paint SLOW DOWN on the road, which is [a minor, admittedly irrelevant form of] vandalism. They did in fact do a crap job so it does in fact look like shit.
These are some people who wanted to live on a dirt road in bumfuck, but when civilization showed up, they didn't move. And let me tell you, their place is a crap little shit-shack, but they could have sold it to a grower and slid out of there long before now, and surely made a massive profit. They could move to some other shit-shack in this shitty town and actually improve their situation but they're married to a particular shitty piece of ground. And instead of making themselves happy, they're standing against the tide and being upset about it.
But civilization always arrives, and if I'd hit that chicken with the front of the vehicle and damaged the plastics, they'd have been liable because civilization recognizes that you can't have chickens running around the road. Instead of moving to where people won't be going by so fast, they demand that everyone else alter their behavior to please them. And the reality is that they could be living someplace nicer if they weren't so addicted to false stability. That little piece of ground could be wiped out by anything next week; since they have grossly inadequate clearings and fire danger has been increasing year on year, fire is a likely candidate. They have no security whatsoever in their tin box that could be opened with a can opener.
Maybe you were raised with a silver spoon in your mouth, with zero experience of the actual struggles and concerns of the majority of working American families.
Well, I was raised with beans and rice in my mouth, and I still think it's bullshit. You don't have a right to make the world stop around you. The only people I feel bad for in SF are the young people trying to get out. They haven't had time to make any money, and it's difficult to make any money in SF while paying living expenses. People pay for part of a room (often one which doubles as a hallway in the crappy floor plans of the narrow dwellings of SF) for what I pay for half a house (shared with my lady.) How is a youth going to climb out of that money well?