Everything is booked and crowded because at the moment, it's a high end destination. But that doesn't mean it really is "high-end" or that it always will be. The quality of the stay or the food varies by location, of course. Some restaurants/hotels at Disney are way better than others. But a survey would likely show a majority of people everywhere (even people who can comfortably afford a Disney vacation) would say it's "overpriced." Is it enough to make people go elsewhere? Apparently not yet. But the prices may be near the peak of what Disney can get away with.
What's happening is Disney is in a favorable environment at the moment. There was pent up demand for travel due to the pandemic. International travel is still cautious and somewhat limited, so domestic destinations are the rave at the moment. Florida is also a state that never really closed down. So people booked their vacations to Florida. Disney is also doing their 50th and there are new attractions. So Disney is a popular destination at the moment. But what happens when all this is over? What happens when the recession hits (even the rich spend less during a recession)? What happens when Guardians and Tron are already open and Universal opens up
Epic Universe in a few years?
Disney is right now obviously targeting the upper-middle class. But what's going to keep the upper-middle class coming back? When international travels opens up more, a lot of this class is going to travel to overseas destinations again.
Disney is doing absolutely nothing to keep people coming back. In fact, they are right now blowing off their most frequent customers (DVC, APs, Florida residents, etc). Most companies work to reward loyalty and see value in repeat business. Right now, Disney corporate does not see value in return customers. They are after the family in the OP's article that will drop $10k for a 4 day vacation once in a lifetime. Chapek even publicly stated so. They see $$$$ in the one-time 7-day guest...not the many times 2-day guest.
And no, this is not the way it's always been at Disney. In 1990, the admission price to enter the Magic Kingdom for a day was $31. In today's money, that's $60. Today, the price for the Magic Kingdom for 1 day is $130. So Disney's rise in ticket prices is WAY above the rate of inflation. Has Disney become more expensive for the average American family? Yes it has. It's at least double what it cost in the 90s.