That was my reaction; I'm not sure how someone could have any historical knowledge and think that. My grandparents were, I think, fairly typical middle-class Americans. They raised 2 kids in a ~1200-sq-ft house in the Los Angeles suburbs, which was considered pretty big. Ate out only on special occasions, maybe 8-9 times a year, never just because they didn't feel like cooking. Did not have "help" to mow their lawns, clean their house, or watch their kids. Bought new devices rarely: it was a big deal to get a TV, and a big deal to get a washing machine. Owned one car, bought used. They sure as hell didn't take extended beach vacations.
I would wager the couple making $300k in SF are not living like that. Hell, I used to live a lifestyle much better than my grandparents did back when I lived in the Bay Area, on a lot less than a six-figure salary. I didn't have kids, but I also didn't even make $50k, and yet I still ate out multiple times per week, not per year.
I know nobody making over $80k in the SF Bay Area who I would not be comfortable calling at least upper-middle-class. The people who think otherwise mostly live in an insane bubble in which they only know people in the top 10% of the income distribution, and have absolutely no idea what a middle-class American lives like.