So how will you find things?
> Ad driven search engines rank ad driven blog spam
We don't have actual concrete proof that Google (or others) rank content with ads higher because of the ads.
As a contrary corollary, generally as society grows, we've seen an increase in "proof-of-person and proof-of-residence on every public X". Want welfare checks or charity, prove yourself. Want to buy cough syrup or booze, prove yourself. Want to drive, want to shoot a gun, want to XXXX.... get an ID.
In early America, men used to vote by everyone going into a big room and shouting for a while (some minor exaggeration). Now you have to register in advance and show ID, and they maintain registries of everyone and their affiliated party.
Showing identity comes with a lack of trust, and volume + anonymity decreases trust as it's slowly abused.