I think most users never even heard about Adblockers or how it will improve their web browsing life considerably. It's the thing people never know they want.

On other story, I give my junior advice that she should install adblocker on her browser, her reply was: "How can I watch the commercial then?" Umm...OKAY.

My assumption:

1) people just didn't know better or

2) they actually loves those flashing ads all along