Earlier quoted context omitted.
Only partially. Spam can be filtered, as PG himself was early to point out, and malware can be countered with better security. This could have been fixed, given enough time. The kill shot, instead, has been delivered by ad-sponsored media; clickbait, fake news, mass rage-storms, fake reviews, etc.
Advertising as a business model causes real damage to the open internet: advertisers censor perfectly good sites because they object to something in there. Slowly but surely, a wide spectrum of ideas and self-expression gets reduced to nothing but sanitized advertiser-friendly content. People can and do censor speech they don't like by targeting the advertisers backing the host.
This is because advertisers don't want to alienate vast populations of people. They don't want stuff like "blacks and women are intellectually inferior, brought to you by Coca Cola!"
I see mainstream ads in "fringe" content of a variety of types, so they don't seem to care much about things being off-beat or strange. They don't seem to care about indirectly sponsoring UFO videos or fringe views of history that aren't transparent efforts to dehumanize people.