That really depends on what their goal is.

From a business perspective it’s not worth fighting to eliminate 100% of ad block uses. The investment is too high. But if they can eliminate 50% or 70% or 90% of ad block uses with youtube? That could be worth the effort for them. If they can “win” for Chrome and make it a bit annoying for Firefox that would likely be enough for Google to declare it a huge success.

People willing to really dig all the way in to get a solution they desire are not the norm. Google can be OK with the 1% of us out there as long as we aren’t also making it possible for another huge chunk of people to piggyback off it effortlessly.