At a certain size, cities seem to tip from "there's always somewhere quality to eat" to "there are more people than places."
And then it's off on the crazy train as to how far down the rabbit hole restaurants want to go.
To be fair, NYC has been doing this a long time (on US timescales).
Nope. There's always somewhere quality to eat. It's just as true in NYC as it is everywhere else.
The reservations described in the article are just there to provide a certain Fine Dining Experience. If you don't want that, go to different restaurants. They are not in short supply.
At some point, it's mostly fashion, rather than being about the food.
So it doesn't feel like something inherent to the fine dining enterprise, but rather present or not in certain cities.
And all large cities have all demographics.
This is just a misunderstanding on your part of what "demographic" means.
In which case, sure, you're right: that doesn't exist in all large cities.