The problem is tracking and dependence on ad networks. Corporations doggedly chasing the bottom line don't want to spend the time or the money to pick and choose specific forums and sites to advertise. They want to pretend to automate that process. Their laziness not only killed the old networks and communities around various product segments, but helped start the "listicle" de-evolution that has decreased content quality across the entire internet.
I used to be able to type in "product_name review" and get some useful, well-known sites. Now I get recycled garbage content, and I have to check all of those sites individually or restrict the domain in the search. It's ridiculous.