Investing in SP 500 is simple and no big deal. But using borrowe

Investing in SP 500 is simple and no big deal. But using borrowed money is different. Rich dad poor dad books describe how he got rate of return = infinity. If you think about it, if one borrows money from the banks, and makes $280k net profit, without using any of his own out-of-pocket money, then the rate of return = $280k/money out of pocket = $280k/0 = infinity.  So that is consistent with what he described.