I agree conceptually with where you're going, but there are problems with this approach.

If there's some situation where taxes are high, but almost nobody falls into that situation, you might find that upon removing the associated taxes, people will structure their affairs to fit the newly created hole in the tax code.

Unfortunately, many complex systems are not created by any deliberate design, but by the accumulation of small decisions which often make sense at the time, but create something akin to horrifying tech debt over the course of decades.

Everyone agrees that the current system is a monstrosity, but there are winners and losers in any attempt to simplify things. The winners might be happy, but the losers will kick up a huge fuss.