Gordie didn't have to. You were not spotting the fact that a comparison with hiring something else other than money (in this case lawnmowers but choose a different item if that makes things easier) didn't highlight the that the hiring of money is treated specially as something the banks can rip savers off with. That other things aren't claimed to be effected by CPI for example, but apparently it's ok to use it as an excuse to pay a pittance to savers and pocket the rest.