Also keep in mind that pirate groups are able to crack L1 Widevine only because some companies let the keys slip in a breach. The keys are burned as soon as they are discovered, making it impractical to disseminate them for public use.
It's only because individual movies/tv shows have a high enough value (versus the cost of cracking it, the risk of your keys being burned) that pirate groups are able to thrive. This wouldn't work well with Youtube as it's value is primarily derived from having a large quantity of content.
I don't think many people would be willing to pay per Youtube video as they do for a movie.
Big tech can afford well paid security teams and uBlock Origin is a bunch of frustrated volunteers who are quitting now they're facing serious resistance for the first time. And Google haven't even exhausted 5% of their options.