Because there is no proof that your assumption is true - people tend to believe they aren't affected by advertising when they actually are. There is plenty of science out there to show the effectiveness of advertising, even if you never click on it.

And yes - growth rates have jumped and in just 2015 it has doubled. Some sites are experiencing 50% ad block rates (in more gaming and technical verticals).

It will become a problem for advertising reliant companies very soon.