"Good" restaurants can become terrible at the flip of a switch.

Usually happens at small local restaurants that get passed off to new owners who think some bean counting is the only thing thay they need to do become a millionaire, fully neglecting any real management and ruin the restaurant before customers fully catch on to the quality degradation.

First a dish is off, but you shrug it off... must have been a one off. Next the steak seems like a different cut, but it still tastes all right and they are running an awesome beer promo. The wife complains the fries are overcooked and cold, they are... but she is a slow eater and maybe it was just an cold plate. Next thing you know they are serving chicken tenders as thin as an I pad, tossed in Buffalo sauce as "boneless wings"

I worked in restaurants that did this, nice ones too.

Anthony Bourdain even wrote about it:

"Recently, there was a news report about the practice of recycling bread. By means of a hidden camera in a restaurant, the reporter was horrified to see returned bread being sent right back out to the floor. This, to me, wasn’t news: the reuse of bread has been an open secret—and a fairly standard practice—in the industry for years. It makes more sense to worry about what happens to the leftover table butter—many restaurants recycle it for hollandaise."

https://www.newyorker.com/magazine/1999/04/19/dont-eat-before-reading-this