In my experience when you don't design and deliver code with testing or accessibility in mind, you end rewriting entire components. This all drastically adds to the end costs. Most leadership thinks this is "efficient" but it's not really. If you do it correct the first time you can consistently deliver features throughout the entire year rather than having to take several months to quickly duct tape everything from falling apart.

I never liked the "debt" metaphor. If a housing developer neglected to build a proper foundation, would you call that "debt?" I feel like it's very similar, it's bad metaphor for a concept that has very little to do with finance.