It's all mental/emotional. In previous eras, being poor meant that you didn't know if you were going to eat that day. Now it means that you have an older iPhone. Beyond your basic survival needs, all money is just a story that we tell ourselves. The poor, middle class, and rich, all eat the same kind of food, drive on the same roads, get treated with the same medicine and wear similar clothes. In the 1500s, a peasant had one or two set of clothes, and you could tell a lord from a peasant by the way they were dressed. Today, there is some psychological difference in an expensive suit vs a cheap suit, but if I showed you a picture of a rich kid starting his internship at Goldman or a poor kid wearing his interview suit, I don't think you could tell who was rich and who isn't.
So to some extent whether you are rich just means whether you can afford your desires, which are related to the story you tell yourself about them and about money. If you like expensive cars and champagne at the club, and you can afford it, then you are rich and if you want them but you can't, then you aren't rich. But if you don't have those desires, you are rich if you can afford the ones you want with no problem. I have one house, one car, one lady and one dog. I like to travel and read books. I am rich because I can afford it. If wanted 3 houses and 3 cars and 3 ladies and 3 dogs, and a ferrari, then I am not rich. I'll stay with the way I am. I like being rich