The Same Phone As Billionaires
I forget where I got the idea, but I'll never forget it. The idea that, despite the vast disparity in wealth between the average person and the ultra-rich, they use the same phones, and the same models of technology generally. Just take some time to mediate on that. Billions of dollars and it is not worth it to buy a better phone than what I have right by my side and can be purchased anywhere electronics are sold. There are a few possibilities driving this, and I don't know what amount each one contributes, but I'll list them here.
Massive Complexity And Economies Of Scale
Designing a complicated electronic device like a phone or computer is a huge undertaking. It takes the largest companies on Earth many billions of dollars of research and design and engineering to create the device in the first place. Then it takes many billions more to make a manufacturing process for a single line of phones.
The humble consumer smartphone often pushes the limits of what is possible with human technology. It's not obvious that we would be capable of making a special phone for billionaires that is proportionate to their massive wealth compared to the average person.
Even if we could, the massive input costs imply that it wouldn't be worth making. The ultra-rich aren't a worthwhile market to serve unless you can charge a lot, and I don't think they are interested in paying millions of dollars for a handheld electronic device.
The complexity of the endeavor mean that only large scale production can be profitable.
Human Standards
Billionaires probably look at existing phones and decide they are good enough. You carry a general purpose computer in your pocket. What more could you ask for?
Win For Capitalism
The bigger point that doesn't apply to just phones is two effects of Capitalism that seem counter-intuitive and maybe even contradictory. Wealth inequality increases in absolute terms, but material living standards become more equal. This can only be a byproduct of massive wealth creation. Material goods become so plentiful that they become relatively cheap even to the average person. An ordinary grocery store can supply rare tropical fruits in a supermarket thousands of miles away in Winter. That's incredible!
Future Projections
It wasn't always the case that all rungs of society use the same consumer technology, and it could change in the future. For example, perhaps customizable manufacturing gets good enough through 3D printing and related technologies that the ultra-rich can afford to make themselves completely custom phones and no one else can. Perhaps in time that technological leap will be brought to the masses too. It's not at all clear what the stable state is. Technology leaps ahead and gets scaled out faster and faster all the time.