I think 21 is talking about the technical side of production e.g. hacking some weird sound effect - doesn't necessarily matter if it was hard, once it's recorde

I think 21 is talking about the technical side of production e.g. hacking some weird sound effect - doesn't necessarily matter if it was hard, once it's recorded and produced, it's done. If you had to have someone holding up a part of the set, as long as it worked, it doesn't need to be maintained. What you are talking about is maintenance of the storyline, which in some ways is probably more consistent with what us Devs talk about with technical debt. That said, there are plenty of plot holes in many TV shows and I still watch them!