A counterintuitive note is that the more expensive restaurants tend to buy the cheaper ingredients. It's kinda the same way with most things; the newb who knows he can't play guitar buys the expensive name brand one. Willy Nelson used the same one for most of his life, with holes in it!
The issue is talent. Someone who has made a name for themselves can charge more because people will pay it. You pay $150 to see the Jonas Brothers. You'd pay $200 to make your neighbor stop singing, not to see him. So when a super star celebrity chef also then uses expensive ingredients for what they know is a big special event for you even if it is they're daily grind, you get $700 gold leaf caviar truffle hamburgers.
On a more day to day level, a hamburger can cost $30-$50 because they did use a waygu ribeye and local heritage cheese with bacon from a private ranch where 60 pigs are fed brandy and chocolate, etc. Other times they just know it's the downtown business lunch crowd that has no issue paying $12 for a grilled cheese sandwich. Rent and taxes alone can often bring fast food chain prices up by up to a dollar downtown vs elsewhere.
As for casual sit down like Appelbees (the next level down being fast casual like Chipolte) it comes down to market niche. Some people want to bring their family to get tater tots and chicken wings for not much money. So they cut corners and work hard to make it edible and affordable, a market that is struggling these days. There's places that cost $50,000 just because they serve it with a $49,000 bottle of wine. That's cheap marketing but people will buy it. There's also homeless shelters. If you identify something someone needs and will pay for and you don't fill that need and make money, you lose. If you follow the bandwagon or food cart more aptly after the fact, you also lose but do more work for it.