I know this is quite selfish but the more accessible youtube-dl is, the more likely Google is to see it as a business threat, and the more likely they are to add some sort of content DRM. Just something to think about
It's coming regardless, as soon as Google can get their CDN efficiency to a point where they can do on the fly encryption of the stream (or post encryption insertion if they can figure out a way to do the key management) with the advertising embedded they'll push the switch anyway, to prevent ad blocking.
It feels like we've backslid by miles and miles since I first got on the Internet in the late 90's. I no longer like this Internet.