There are certain foods prepared in restaurants (generally--not in every instance) that are no longer as delicious as they used to be, often due to laziness, the cooks' preference for a preparation which takes less time, is less expensive to make, where the ingredients required to make the dish are difficult or near impossible to find (but were not before), or due to supposed health considerations.
A few examples of these sorts of decline are pizza, gyros, and McDonald's french fries. Pizza has declined because cooks used to incorporate spices into the pizza. Then people started asking for them to (for example) leave out the oregano, or garlic, or basil . . . Pretty soon cooks decided to omit all these spices and others from a pizza and just leave oregano and garlic powder on the table to be added afterward. Hence, in your average pizza place, you now get an incredibly bland pizza. And, no, adding garlic powder later does not cut it.
Gyros used to be marketed (by the Parthenon Restaurant in Chicago which set up a separate corporation to do so) with a gadget that played a gas flame along the entire rotating length of the spicy formed pork/lamb/beef(?) cylinder.
This was essential to the preparation of the dish because its essence required that the dish be prepared from thinly sliced pieces of CHARRED AND CARMELIZED meat about two to three inches wide, sawed off the very edge of the rotating cylinder of meat. By design, the gas jet supplied an endless amount of charred and carmelized meat. Now, restaurants just order the meat cylinder and warm up the meat in an oven (I am guessing) or microwave it, resulting in no charring or carmelization. It tastes like glorified meat loaf.
The famed McDonald's fries are a shadow of their former selves. They are no longer anywhere near as crunchy on the outside and tender-soft on the inside as they used to be, since McDonald's stopped frying them in beef fat.
I attribute the pizza and gyros declines to laziness, speed and cost. The McDonald's fries decline is primarily a chimeric quest for health. Whoever heard of a "healthy" French fry? But I will bet you that the liquid oil now used is cheaper than beef tallow, as well.
Can you think of other restaurant foods which have declined over the years and cannot generally be found in their once superior forms?