Maybe think about it in a different way. Right now, there is a kill-switch within googles primary product that could essentially destroy their business model.

This is not about google wanting to harm the current power users. It is probably the idea that someone could come along and destroy their business.

If such an extensions goes mainstream that could seriously harm them.

They may also want to get rid of paying Adblock Plus money for their highway robbery.

Now that I think about it, getting rid of ABP may be the primary reason for this move. They have to basically pay a third party to get access to their own users.

Either way, the battle is not over the power user minority, but over the average user.

The idea is to make the API just powerful enough for the most annoying ads to disappear. Most users would probably be content with this. They will probably make it so they won't lose all of their power users. I think what they really want is increasing the amount of works it takes to have full adblocking functionality to the point where the average user has no access to it.