By the time that outstanding tech debt becomes truly problematic, the original authors have most likely moved companies. I think a lot of people know this deep down, which is why so many of them don't go as far to build things on a maintainable way. There's economics for the company, then there's economics for the individual engineer.
Similarly, fixing that technical debt will likely look like pure overhead while the benefit of "other people will finish future features faster and with fewer bugs" gets socialized, realized diffusely and goes largely unrecognized (except, if you're lucky, by the other developers themselves).
I learned that one the hard way. Features get priority because features have got visibility.
The picture gets even worse when you consider the probability that fixing technical debt will break things.
Even if they were still at the same company they'd have moved on or been promoted so it's unlikely they'd be asked to maintain.
In my own experience though it is one reason I left my last job. 2 year of new dev, 3 years of maintaince with no end in sight. GPU related stuff, new GPUs come out with new drivers all the time. Working around those bugs so the people using my code don't have to deal with them. There is some feeling of reward but it's mostly no fun.
Even in my personal projects the more I have the more maintainance piles on. Browsers break stuff or warnings about libraries. Each project adds X more notifications a month. At some point I'll be overwhelmed with maintainance notificications and have no time for anything else unless I ignore them.
