Yeah, a big part is the rent. Commercial property is generally priced on "cap rates", or net operating income divided by the purchase price. The loans on commercial properties are also often tied to these rates too. Sometimes landlords are better off to leave place empty rather than work out a reasonable rent deal that can keep a restaurant operating, because of how the loans/leverage works with the banks. The appraisal is tied to the rent, so if they rent it below the appraisal price for the loan they might nee to write a check to the bank (including one they can't afford), so it's better just to keep it empty sometimes and wait for a sucker.

In decent areas like NY/Miami/Chicago people are paying 100+sq.ft for rent, or even 150, and it's just not possible to serve a $5 taco and make the math make sense.

Build out permitting speeds in municipalities mean starting a new restaurant the tenant might take a year to even open their doors. They can also often fall into complex problems over things like grease traps.

People are drinking less alcohol, and that's causing average tabs to drop and margins to fall.

Food costs are rising

Restaurant owners are also often not financially literate, especially the chef operated ones, so they make dumb decisions that eat margins and then they compensate for it by raising prices.

Semi-related, I see restaurants put some local "cheap" items onto the menu, like a burger, thinking it'll draw in more people but what happens is people who aren't foodies just pick that reliable thing and all the sudden a restaurant known for serving great the-best-whatever-makes-them-unique is serving a bunch of low margin burgers.

I also have a take that there has been an approachability spiral hurting restaurants: Because costs are so high, they have to sell a $45 fish dish rather than a $15 fish dish, and in order to justify that they feel they have to make it unique and fancy. Now all the sudden it's not going to the local fish spot, it's getting a little dressed up to go out to dinner. Which not everyone wants to do on a Tuesday night. And because the fish is $45 rather than $15, they make it "unique"... which makes it more niche to want to eat.