They can fight all they want. In the end it doesn't matter how many engineers they throw at the problem. The only way they can win is for the world to descend ever deeper into DRM tyranny. Google must literally own your computer in order to prevent you from copying YouTube videos. It has to come pwned straight off the factory so that Google can literally dictate that you the user are prohibited from running certain bad programs that are known to hurt their bottom line.

I realize we're not too far off from that dystopia but it's still a battle that deserves to be fought for the principle of it.

Sure. We can also control those variables. Youtube-dl has a small javascript interpreter to figure out the audio and video URLs that YouTube generates for every client. In this thread it was also pointed out that people can use headless chrome.

It's simple. If they allow public access to their site at all, there's pretty much nothing they can do to stop any of this.