It's not your responsibility. That's why Google makes you do it (pay or watch ads). Otherwise they can't pay creators and if they don't get paid then you don't get content you like to watch. Lose lose. So I'd say they kinda figured it out.
> if I look away and mute, which is perfectly allowed, versus use an ad blocker, what's the difference?
The difference is you still see the beginning of the ad and some people see a big part of it because they don't have the habit of muting and looking away out of fear of missing the beginning of the video for example.
> The outcome for me is identical. I don't see an ad, and I won't buy something.
You still see the beginning of the ad. Whether you buy something or not is not always what the ad is trying to do sometimes it's just raising awareness
I am not Google's accountant. They can figure it out.