It’s not the tax rate that matters, it’s what is actually paid.
actually both are important, the when rates get into the 20% range, individuals begin to redeploy assets away from productive investments to tax avoidance strategies. That’s the basic reason the fed gov has never had tax revenues greater then 20%. It also tells you where the sweet spot is on the laffer curve. In other words, flatten the tax code, while dumping all the carve outs, and you’ll increase tax revenues as well as income.