IRS data shows thousands of millionaires

There is 1.8 million of unemployed people on unemployment insurance. Thousands is a drop in the bucket. You are looking at saving, what, 0.1% of the admin cost because a couple thousand people use it that don't need to? You are literally looking at saving around 26 million dollars per year with this measure (maximum payout is $500 per week). That's nothing for an agency that spends over 100 billion per year.

I don’t see inflation getting so bad that anyone with a million dollars every year need unemployment to survive in the next century

At 3% inflation in 50 years, 500k will be like 100k today in 50 years. In 100 years, 2 million will be like 100k in today's money. It does not take long for inflation to catch up. 3% is the historic average for inflation in the US.

This is an old conservative trick, don't fall for it. If we must have means tests, they must be indexed to inflation otherwise they turn into rollbacks of social programs with time.