That doesn't matter. As development stops, youtube-dl will stop being able to download videos in a matter of months (at best). This is an extremely brittle system that relies on youtube-dl being one step ahead of Youtube at all times. Without further development, the next update to Youtube's site will break the tool.

It was really a matter of time. I'm sure most of us were already amazed it lasted this long - and it did because it remained a relatively obscure tool for years.

It's also the case that the development of subversive/illegal tools requires a certain amount of subterfuge and sneakiness that the youtube-dl developers apparently weren't ready to engage in. While this is understandable, it also underscores the fact that such tools live on borrowed time (as does, I would argue, general-purpose computing itself).