The interest on technical debt may be high, but you don't have to pay it if the product becomes obsolete, replaced, unsuccessful or improved. Basically you only

The interest on technical debt may be high, but you don't have to pay it if the product becomes obsolete, replaced, unsuccessful or improved. Basically you only need to pay the debt if the product is successful/used and not fixed, which in terms of overall risk is very different from a loan that you need to pay back no matter what. (It's sometimes perhaps more like VC finding - a very high cost for the provided up front money, but only in a small set of circumstances where the overall success makes the cost relatively small)