I like the intention, and I hope to see more of this... but it's kind of hard to imagine that the end goal here is "Responsibility", when the business goal is "how many ads can we sell?"
In the meantime, they're bleeding man hours, money, ad impressions, perhaps advertisers targeting the audiences which are being culled.
Now examine the question: What does Google have to gain by appearing to put a genuine effort into this while not actually addressing the problem?
They gain a whole lot more than in the first scenario - new users hopeful of an increase in quality, support from privacy and attention-span advocates, insight into how they can influence, suppress, or promote certain themes going forward, more metrics to become more entrenched in the data harvesting machine learning game...
There are more and more people that do nothing but be on the internet all day. Advertisers don't want those people, they want social people that watch YouTube on the side, and are likely to buy products too.