The problem with this is that it would at most replace a fraction of income taxes.

My theory is that it's just another lever that's being pulled to centralize power in the executive. The president can pick winners and losers because the power to levy tariffs is surgical, and so individual companies can be targeted if they don't fall in line with the dictator's whims.

Imagine Apple facing 1000% tariffs unless they take down content that's critical of the president. It's not outside the realm of possibility.