But those have a tangible return to society that people flock to. Almost the entirety of Google products is open to anyone on Earth to just open up an use because that ad model is so successful. People click high value ads and it covers to cost of video distribution to anyone with an cell phone and wifi.

Jane street on the other hand is arbitraging against regular folks money, so they can distribute the gains to their select high value clients. There is no free office productivity suite and limitless "How to repair cell phones to start your own business" videos distributed to everyone for free.

In a way, they are doing opposite functions. Ad media takes from people who buy stuff and gives to people who don't (or cant't) buy anything. Jane street and their ilk take from regular people and give to those who have everything already.

Your "ad" people are rotting the brains of entire generations by addicting kids using many different tactics (insta, YouTube shorts, TikTok....) . Please spare us the moral judgement.

"brain rot" is a subjective criticism. objectively speaking, the kids are making art and sharing it with each other. it's at worst an extension of the entertainment industry. you can not like the art, but it's at least art.

the finance industry doesn't produce anything of value. it just turns $1 into $2 and liquidates productive industries.