I think your last paragraph is the answer. Targeting ad with personal information is questionably profitable to me. I am almost not caught by the ads in websites but by some search results (google search first page) or article in forums like here or reddit or some people I followed. Maybe Google just find out they actually do not need such garbage personal information. I said garbage because lots of them are really caused by random events (sometimes you are interested in something. But after that period of time, you would not ever get in touch with it again) or fake information. And, the ecosystem to store these information is expensive.