I can only speak for the UK but for quite a while now, McD's has become an uninviting experience, with miserable staff, menu screens that visibly tell you to hurry the f*k up and choose the product. Not to mention customers vying with delivery drivers for orders. I think the problem applies to all-income customers.
My experience is that quality in McD is rapidly declining. We may agree was never a Michelin star restaurant. But I remember being more or leas enjoying the food. Now I just can’t. Maybe I’m getting older. But I would swear the quality is much worse now than say 5 or 10 years ago.
Also, the quality of a fast food restaurant (cleanliness and service) is directly correlated to the median income of the area it is in. Wealthy suburbs will have much cleaner restaurants than inner city restaurants from the same chain.