A million or more 18-20 year olds could no doubt truthfully report 6-figure household income. To me, that's "many".

(Slightly over a quarter of households in the US have a household income over $100K as reported on tax returns. Household income for the purposes of credit application can be meaningfully higher than for adjusted gross income tax return concerns.)

That's actually an interesting stat. If there are ~115 million US households and 20% have > $100,000 income, that is ~23 million households. If 18-24 year olds make up ~9.5% of the population, and we 'assume' they are evenly distributed in these households, then this statement (well 18-24) could be true.

Per this: https://dqydj.com/household-income-percentile-calculator-201...

it's 26.3% of households with incomes over $100K. I saw another estimate of 125 million households, so it could well be ~33 million households with >=$100K household income.

(I'm not so much quibbling with numbers as trying to get across that "it's a lot of people")