Oh, but it will not be GOOGLE’s next step. I dont think it is the goal anyway. They only need to help site owners to sign up to their WEI thing, and there will be oh so many incentives. Google will be happy to license it out, or even make the toolkit fully opensource, to whoever wants to implement it in their browser, regardless of the engine used. Their obvious ultimate goal is to show the ads with no interruptions, which also happens to be the desire of most of the websites. And many websites will willingly implement it on their side, they do not really need too much encouragement.
Adguard - the paid one - was the best purchase I made in a year. And there was tough competition for this spot.
I appreciate the desire to go all FOSS, but there is still the need to feed all these great people who make it work.
Do not stop yourself, get it!