Many mega-wealthy looking people have tons to debt, so net worth-wise maybe they aren't mega-wealthy after all.
When I was still a tax preparer, I did returns for plenty of clients whose income was top 10%, 5% and even 1% (of course these are the kind of people most likely to need professional tax services as that much income typically comes from something far more complicated than a simple W-2).
When I got that job, I had just come out of paying off a lot of personal debt and I was saving up what little money I could to be able to afford to quit that job and move somewhere I could get a better job after graduation. Grad school was a huge cash suck. So understand, with everything I had in the whole world, I was worth $10,000 or so in terms of net worth.
The thing I realized though, after doing enough of these (because you have to review their statements to figure things out), is that I was actually wealthier than at least some of the people who earned salaries in excess of $100,000 a year Granted, this circa 2010.
The thing is, when your income is sufficiently high, people will throw loans and credit at you, and if you have a lot of debt to begin with they just increase the interest rate.
Numbers can lie to you, but in this case they didn't. I saw people with $160,000 in annual income with $30,000 in credit card debt, $60,000 in car loans, $450,000 in mortgage, around $100,000 in a potpourri of all kinds of other loans like HELOCs, with around $15,000 worth of taxable investments in very expensive mutual funds from Edward Jones type places and maybe $5,000 in cash.
Absolute madness. The thing is, if they kept the payments up, their debts never got any smaller because as soon as something was paid off partially they just borrowed more to spend again.
I will grant you, these people had amazing lifestyles. Custom clothes, constant trips and vacations, expensive and fancy cars, dined in restaurants almost daily, well stocked liquor cabinets, etc. Like people on TV, larger than life. But I couldn't do it, the debt burden would drive me insane.
It is not a majority of high income people, but people with large incomes, luxurious lifestyles, and no wealth certainly exist.