A Rising Tide and Usury

The phrase 'A rising tide lifts all boats' entails that 'a rising tide' cannot be a Zero-Sum condition.  It seems to connote a period of universal growth, but concrete details are usually lacking when the phrase is uttered.  Nevertheless, one Economic process that it cannot involve is Usury, i. e. lending at a rate greater than 0%.  For, plainly, Usury at any rate is a Zero-Sum transaction, regardless of time-lapse or circumstance, i. e. because gains exactly the increment that borrower repays.  Thus, Usury cannot be part of the kind of period of universal growth signified by the image.