There is already an income tax for interest earned after that money has already been taxed as income (of whichever kind). And dividends are already taxed as well as capital gains... You can only carry over the capital losses which can offset $3k worth of gains but all of the gains get taxed in the year you have the gain. After that your accumulated wealth is taxed yet again when you die!
How does that work? You just have ONE tax collection , or do you intend to retax the same money each year?
Dumb idea is dumb
A better idea is to tax all sales. You buy it, you pay a sales tax, NO exceptions , no exemptions. Quite obviously the rich purchase more than the poor and so would Spend more than the poor.
Last year Americans spent $10.7T . The federal budget has been averaging around $3.7T.
National sales tax of 20% give you $2.14T. I'm fairly certain we can make enough cuts to make that work.
And that puts more money back in every tax payers pocket.
but it won't ever happen b/c no one really cares about doing the right thing.