If the architecture of the web changes to one where people only see content that they've asked to see, and that kills advertising, it would also put a significant damper on anyone else whose business involves injecting unwanted content into a viewer's consciousness. Propagandists are the first to come to mind.
If it can become prohibitively expensive to sway an election by tampering with people's information, then the alternative (policies that actually benefit the people) will become more popular, leading to reduced unrest.
Democracy is having a bad time lately because its enemies have new weapons for use against it. If we break those weapons, it starts working again.
What I said is that adtech systems are also used for it. So if they were to disappear overnight, a _proportion_ of those activities, and a pretty large one I reckon, would also disappear.
It seems way more likely to me that they would simply adapt, as they always have.
Social media and any media platform also enables the spreading of propaganda, but it's not as systematic as the tools built for advertising.
Basically, adtech is the backbone of the attention economy where more clicks = more revenue. So the incentives are to always say the most inflammatory clickbait you can, to incentivize profits. Sensible and boring stable takes and agreement will always be stifled to promote outrage, beefs, and clickbait to maximize revenue. To generalize; stability in any general field like politics or journalism gets turned into obnoxious grandstanding to be more like reality tv to get more attention. In software, people who monetize off advertising are incentivized to build dark patterns maximized on attention grabbing. Whereas without advertising as the main source of revenue, people stop building dark these patterns to steal your attention, as you are paying them directly for a service, so you are the customer instead of the product.
