What are you basing that on, without knowing any financial information? If the mere existence of millionaires makes a massive company viable, then what company isn't?
Do you believe that the very wealthy, today, are doing these things themselves, and that an Uber courier is solving a huge problem for them? Paying people to deliver stuff isn't new. Neither is driving people around. What Uber has done is made in convenient and, thus far, inexpensive. Do you think Uber will reap massive margins here? The barrier to entry is very low.
If Lyft is burning $50M/month driving me across town for $15, or me and two strangers for $5 each, how does substituting a person for a dress or a shaving kit or a bag of groceries suddenly make it hugely profitable?
And if this is the case, why isn't Postmates / Instacart/ etc. getting billions in VC money to expand and corner this underserved market? Why did all the courier startups immediately go belly up in the dot-com bubble last time around?
A few? With between 11 and 13 million millionaires in the US, it's a $60 billion business. And that's ignoring the vast number of people in the US earning $150,000+ in a household while not being millionaires; people that can easily afford such services.
And then there's this:
"The Richest Generation in U.S. History Just Keeps Getting Richer"
http://www.bloomberg.com/news/articles/2016-07-12/the-riches...
The boomers are getting older and richer, and will benefit massively from courier services.