Or the economy is stimulated less than usual, and you end up with less total wealth growth between the two of you.
By the way, I made the "monkey" crack before I saw the thread on monkey economics. It is worth watching the video.
People do tend to make decisions in relative terms rather than absolute ones.
But notice he could have also said, I loaned out all 1000 BTC at -50% interest and get back 500 BTC which is worth the same, but I've done a wonderful thing for society and it cost me nothing.
Or I loaned out all 1000 BTC at -35%(ish) and ended up with 650 BTC worth 1,300 loaves of bread. whether or not it is a good argument depends on the random absolute numbers you pull out of your but with the flying monkeys.
But in the end, humans don't tend to make decisions this way. We say minimize risk if we expect to be gaining value. Gamble overly optimistically if we think the trend is down, but there is a chance we might be saved from loses. Las Vegas was built on this principle. Ask the monkeys.