In the future there won't be any technical debt. You were lucky to live early. Code, most code, will eventually turn into some sort of sanitised applied maths corpus (with a heavy overlay of "AI" analytical tools). In applied mathematics you have cultural obsolescence (stuff that we no longer find interesting or relevant, like an asymptotic formula for the Airy function [0]) but the corpus is intrinsically add-only.…
I agree with you. That end state is of course all open source. Anyone not working toward that state is making money (understandably) as the higher priority.
I'm still not sure why businesses do so much proprietary customization as opposed to working in an upstream OSS project. I suppose the OSS foundation in those cases isn't solid enough yet.