It's not that they have documentation as much as it is that the tax code is more subjective for high earners that run businesses, because what is an isn't a leg

It's not that they have documentation as much as it is that the tax code is more subjective for high earners that run businesses, because what is an isn't a legitimate business expenses or R&D or whatever is not always clear cut, and the tax code gives a good amount of leeway. And even when it doesn't give much leeway, it's still a lot of work for the IRS to prove their case unless the fraud was explicit and deliberate. The tax code is this way on purpose. It's designed to encourage businesses and people to spend.