People underestimate the income of the top%, researchers find (phys.org)

For the top 1%, income is irrelevant. It's the net worth that's important there. Median person has no concept of that. So those surveys are bound to be bs.

The top 1% is very different from the top 0.1%. You are still likely a W2 earner earning < 1M and paying 40%-50% tax rates if you are in this range; lawyers, doctors, well paid engineers, etc.

I don't know why the article mentions "billionaires", who are in the top 0.1% and are the ones paying almost zero tax because they just borrow against their investments.

The top% doesn't have income. To be in the top 1% you need something like $20M.