That can’t be right. A burrito or sandwich costs $18-$20 after tax, health mandate etc, and that’s at a walk up and buy kind of place.
If you get fries with that, it’s another $6-$8.
A sit down meal? Probably 50% more. I don’t see how $32 is a reasonable estimate.
I’d guess closer to $50
That being said, I think it's a bit disingenuous to compare cost of living like that. If you enjoy living in a large city, you probably have a lifestyle that isn't possible in small town America and you're probably willing to have a smaller living space in order to have that lifestyle. For me, living in a city means there is so much to do that I can pretty much just use my apartment as a place to sleep and spend most my waking hours somewhere else. That's not for everyone but if it is you, you'd probably be way better off making 300k in sf than 100k in the middle of Kansas.
On the other hand, if you don't go out much and spend most your time at home and want a large house to entertain guests and raise a bunch of kids and have 100 acres of land to ride your dirt bikes. You're probably better off trying to do that with 100k in Kansas.
For rent, a median one bedroom apartment in SF would be $14-18k/year more than a median one bedroom apartment in Seattle, Chicago, Nashville, Orlando, Sacramento, Austin, or Fresno.
Average monthly spending on food in SF is about $150 above the national average, so that's another $1800/year you need. But that probably includes a lot of people who do their own cooking. Maybe tech workers need to buy all their meals. I found a tourist planning site that said the average tourist in SF spends $32/day on meals, so let's use that instead of $150/month above national food average. That would mean we need $12k/year extra for SF for food.
So someone coming to SF from one of those other places needs an after tax income that is equal to their after tax from their $100k in their old city, plus $30k after tax for rent and food.
That requires a salary of $148k.
That's a long way from $300k, so what other costs are missing?