You don't become a billionaire by playing by the rules.
Actually you're wrong about that.
These guys do play by the rule: they obey the law to a tee. But... they obey the LETTER of the law, not the spirit. That's why nobody can't stop them and throw them in the slammer for tax evasion.
What you need to be a billionaire is to be psychopathic enough to think you're the only person whose interests matter, and have enough money to pay for equally psychopathic tax lawyers to establish some legal constructs for you that enable you to pay almost zero taxes legally. Once you're rich enough to pay the lawyers, you get exponentially richer.
It's legal, but they're still psychopathic sonsabitches.
I watched the trailer, and it looks like a right ole shite action movie. However, I will say this:
Why is fiction always better than reality?