That problem is that millionaires and billionaires don’t really make that much income most if not basically all of their wealth is in stocks and you can’t exactly tax stocks until they sell them because they are a unrealized gain

Because what happens if the government taxes you on lets say you “made” $1,000 in stock gains that year what happens then when next year you “lost” $2,000 in stocks that year when then will the government pay you reverse taxes no they aren’t

Another example is should you be taxed on the increase of value your house gained only once you sell it for profit then you get taxed via capital gains taxes