But, as a percentage, what subset of all rich people actually earned their money through technology? Either way, if those people aren't leveraging their home equity, than they don't know much about finance, truth be told. Assume you have good credit and a steady income or assets; there is absolutely no reason to own your house outright. Bill Gates, for example, has a mortgage on his house. The easier way to think about it is that if you're paying 5% interest on your mortgage, but could get 7% return on money elsewhere, you should take all the money out of your house and earn the 2%. Either way, you also get the value increase (or decrease on the equity as whole). This is the same reason that many wealthy college students take out college loans, because with their low interest rate, there is no reason not to have the 40k sitting somewhere else making more money.
I don't know what evidence, other than opinion, you have that rich people don't have a special guild of concierges, or rent handbags or Ferraris. I know several people of the private jet sort who do have an assistant that is not just someone who just takes down their schedule, but rather is someone who can solve problems anywhere, work the network to get a dinner reservation where ever you want, etc. Further, most fabulously wealthy people are very smart with their money, even if they do have ten houses and two yachts, and although they could buy $2000 bags and throw them away in two months, why would they? They could buy a fancy sports car, an asset that radically depreciates and that you can’t drive all the time, or they could rent one whenever they want?