> Because there is no point in being frugal if you have to pay significant corporate tax. And it helped expand "the empire" he was building, because he could reinvest everything.
Only profits are taxed, not sales. So if you "reinvest everything" you are not going to pay taxes.
You can hire more people, buy other companies, rent more equipment, etc. The net result is that the company grows but has no profits. It doesn't work if it buys real-estate, for example, as that increases the company value and the owner then needs to pay for the increase of the value of the company. But then it's on the share value increase, and not in profits.
High taxes can incentive grow as spending money to grow it's less costly than to capitalize profits. That's why lowering taxes is seen as an opportunity to withdraw money and reduce investment.