Most of the money belongs to the middle class, not the rich. So that is what markets mostly work for.
If you want to make money from the middle class, you have to do better at something than whoever is doing it now.
If you want to make money from the rich, you just have to dream up some new twist on their wants (sure, it has to be executed reasonably well, but you're not competing in the same way).
So sure, most of the money that changes hands does so via the daily/weekly/monthly spending of regular people. But that's not where the big money is unless you come up with a truly mass market new thing. The big money is in providing for the wants of the rich, because the marginal utility of what they spend on wants is so low to them.
Markets care about "aggregate demand". Rich people can be lucrative individual customers because they have more to spend and often less price sensitivity. But they have limited capacity for consumption in many areas; they only eat three meals a day and only fill so many airline seats at once. The middle class and even lower classes have much higher capacity for consumption and are worth targeting - think McDonald's or even Google (advertisers want all the eyeballs they can get, even if they prefer wealthy ones)
This is easily and provably false. A single-digit percentage of households holds over well over half the wealth.
Not sure how that breaks down.
The top 10% holds 69%.
https://www.stlouisfed.org/institute-for-economic-equity/the...
A young doctor with $100k in med school loan debt is part of that “bottom 50%” of wealth but nonetheless an extremely attractive target for “the market”.
In a healthy competitive market, they're also reactive to customer desires, but when they're presented with the opportunity to decrease competition through consolidation or other means, it's blatantly obvious where their true loyalties lie.