We are facing the destruction of the middle class and these thinkers are oblivious if they are thinking that cities need to look at the essentials that have made great cities in the past. I think the most important item is safety and that indicates that the cities of the future will need to be self defended compounds....moated cities.
I think one of the problems with the “middle class” is defining it. For instance, in a high cost area such as DC, New York, Chicago, etc., a family making 80-100k is probably closer to middle class than a family making that much in St. Louis or Cincinnati, where you might be closer to upper middle class. That’s why “middle class tax cuts” don’t help a lot of people living middle class existences in high cost areas.
You are right about safety. People who don’t feel safe where they live and can afford to move. move quickly.