I assume they don't do the work themselves, they pay a tax expert. If I was a rich businessman I wouldn't want to spend any more time than necessary thinking about taxes

You wouldn't spend any time. You would pay a CPA $300K per year to save you millions in tax liability and never even think about it.

Or decades ago you'd face a 70-90% tax rate, stop fighting it, and be happy with an upper middle-class life. Unless you're a certain washed up actor turned governor.