There's a classic saying "good fast or cheap - pick 2!"
McDonald's used to have the golden goose of being all 3. (and that's probably why they rocketed to success) I recall in the early 90's the burgers were juicy, the fries hot and you could get a value meal for $2.99.
Inflation adjusted that's $5.02 now - yet most of the meals are $7-$8. And everything tastes dried out, like it's been sitting forever.
Places like Culver's or Chik-Fil-A used to be "expensive" compared to McDonald's but now they're the same price with much higher quality - pretty easy decision for consumers!
The closest you get to "classic McDonalds" is in an airport where everything is hot and fresh because it's so busy.
But the average brick and mortar? It's now "crappy, slow and not cheap" - 3 strikes you're out.