I think a big part of the problem is that no one really seems to know what "rich" looks like.
People have an image of what ultra rich looks like from TV and movies, but actual "rich" really looks A LOT like middle class life, it just costs a lot.
Two people can live essentially materially identical lives:
-nice detached home
-two cars
-kids in good schools and activities
-yearly vacations
-maybe even own a cottage
And that life can range from costing mid 5 figures to several hundreds of thousands depending on location, what finishes are in the house, what kind of cars, what the public vs private school situation is, what activities the kids are into, etc, etc.
Until someone gets to the level where they have a house with maid's quarters and multiple live in domestic staff, and a private jet, then the lifestyle of the rich really isn't really any different from what everyone pictures as a normal, middle class life, at least not in the broad strokes.
A different way to put it is the "normal middle class life" can be really, really god damn expensive. Pete has written about how a low 5 figure life can be virtually identical to a high 5 figure life depending on how wasteful someone is with their spending. Well, that logic extends well into the hundreds of thousands life as well.
DH and I have a low 5 figure base spend and most of our friends spend at least a hundred to a few hundred thousand per year, and our lives really aren't so appreciably different.
Like sure, a colleague and I just both bought new homes (mine under 150K, her's 1.4M) and both kitchens were dated and had bad layouts. She dumped 45K into hers, and I spent about $500 on Ikea modular cabinets, bars to hang pots on my wall, and a plug in chandelier so I wouldn't have to hire an electrician.
Her kitchen is like something out of a magazine, mine is a franken-kitchen with half of the cabinets nearly 50 years old and original to the house and the other half from Ikea, and no, they don't match at all.
I'm a former chef who knew exactly what she wanted and mine is actually my dream kitchen now, and the mix of elements is actually so eclectic that it looks kind of cool. It's perfect for me. Her kitchen looks like something you probably shouldn't touch, and the layout the designer put together is, well, okay, but not overly efficient for actual cooking.
In the end, she spent 90 times what I did, and the real life difference between the two is that they have a different esthetic style and slightly different efficiency in layout.
Both kitchens are solidly, middle class lifestyle. Neither are overly huge or overly small. Both are customized for women who will stand over hot stoves cooking for their families (her's a several thousand dollar Bosch gas range, mine an 'apartment size' cheap thing that came with the place.)
I'll spend about $200 per month on food, she'll spend over $2000 because her two sons and friends like a lot of brand name stuff and they eat pounds of it, and her husband insists on a lot of steak nights, plus none of them will eat leftovers, so their food wastage is massive.
We both love a good restaurant meal. I just went to a local Ethiopian place and shared an amazing meal with my dad for $20 including tax and tip. She just took me out for a meal at her favourite restaurant, where a mediocre glass of wine costs more than my Ethiopian meal. The food was pretty good, both were nice experiences.
I drive a used Corolla, she drives a leased Range Rover. We both have remote car starters, but I have heated indoor parking at my building, so I don't have to clear off snow all winter.
I have a $30 Aeropress and a $100 Breville milk frother. She is known on sight by every Starbucks employee at the locations near her house, work, and gym.
I just booked a trip to Europe, which will be a self-guided road trip through small towns, off season, for $2600 for two, including breakfasts. She is taking her brood to Italy over Christmas, and the business class flights alone will be at least $16K.
I colour my own hair and maintain a low maintenance hair style, she gets her hair cut and coloured every 4 weeks for $600.
Both couples are active. I have a gym and pool in my building, public baseball diamond, tennis and basketball courts across the street, and DH bikes and runs all winter. She and her DH have $800/mo gym memberships each, she has a trainer, he also has a golf membership, and the whole family loves to ski ($$$$$).
Her household spending is enormous, but really, our lives aren't appreciably different in functional terms.
The thing is that as you go up in luxury in life, the cost rises astronomically, but the outcome changes only marginally.
A stone countertop is only so much nicer than a laminate, an expensive restaurant has food and service that can really only be so good, an extremely expensive car in morning traffic is still just a car in traffic, a several thousand dollar chandelier doesn't light much better than a $100 plug-in chandelier from Ikea, a several thousand dollar watch and a drug store watch both tell time, and the latest iPhone vs an older phone both work pretty comparably.
The incremental increases in quality and experience start getting proportionally so much more expensive that it can cost nearly 10X to live a life just superficially better than someone else's.
My colleague and I have the same job, and per hour, I actually bill more than she does. I said that our lives are pretty similar despite our wildly different spending, but that isn't strictly true. She works 6 days a week, and I work 1.
So in truth, our lives are RADICALLY different because of our spending differences, just not in the way people might think.
So yeah, it's very difficult to define "rich" because you need to be rich to afford a lot of seemingly middle class lifestyles.