Sf has some great hole in the wall places that aren’t too expensive. E.g. Tonga room isn’t that badly priced

Dropping 50$/person on dinner & drinks in sf isn’t that much money when your rent is 50x+ that figure.

Tonga room is a terrible example because, as someone else mentioned, it's a bar in the Fairmont.

If you want a great literal hole in the wall, try Yamo in the Mission. Burmese food, grand total of 6 seats (all at the bar) in the restaurant, and the entire kitchen is right in front of you. $6 entrees.

The SF Bay Area as a whole has some great holes in the wall, and there's even still some in San Francisco proper if you dig around, but in addition to being a bar in the Fairmont as others have noted, the Tonga Room is a world-famous tiki bar that opened in 1945, with two themed dining rooms that wrap around an artificial lagoon with a "rainstorm" every thirty minutes. That's a really weird definition of hole-in-the-wall. :)

While I haven't been up to SF proper for food and barhopping in a few years now, the Lark up in the financial district is much more of what I'd call a good cheap bar. I tend to bristle a bit at people dissing the SF food and drink scene, but I have to remind myself that with few exceptions my favorite places in the Bay Area aren't actually in SF itself. The metro area as a whole has virtually everything you can imagine at a very wide range of price points. I suspect one could make a case that the most interesting stuff happening is in the East Bay and South Bay, though.

A bar inside the Fairmont hotel could hardly be described as a “hole in the wall”

This is enough to say that then it isn't comparable. "There exists" is only a useful quantifier in mathematics. "There exists" better food elsewhere if you idk pay a world reknown chef to cook you a meal herself for $5000.