1. That kinda already happens to a degree. A significant part of the youtube audience is outside of US & Europe and so those users are worth less to advertisers because advertising budgets are somewhat proportional to the population's disposable income. However youtube still has the same cost whether they're serving a user who advertisers would pay a lot for or a user where advertisers won't pay a lot for.

2. That's just making the experience worse for the people who do watch ads. Imagine it's a restaurant and you're raising the price so half the people can eat for free (this way everybody stays happy).

Ad networks work on a bid system. If the impressions/clicks were worth more, bidding would be more competitive and prices would already be higher.

Why should advertisers pay more for ads that fewer people watch? Why would an advertiser be okay with sponsoring people that avoid their ads? It's not the advertisers' jobs.

Neither is it my job to buy the advertisers' product. Why should the advertiser have to pay for being shown to people who are so hostile to advertisements that they would block them if they could?

When I used to watch broadcast television I used to do the utmost to avoid the ads by muting during ad break. However, on the occasions that an ad would actively interfere with my watching experience, such as an animation on the channel logo, or a sudden ad break with an ad premeditatedly designed to catch you by surprise (often by "sponsors") I made an explicit decision to boycott said product if I had an opportunity. There are brands that I stopped buying because of these things.

Those people are more valuable:

People who react with antipathy to ads have been removed, increasing the value of the brand messaging by negating brand damage in large-scale ad campaigns.

Because there is no alternative to youtube for putting ads in front of the entire internets video hosting service. Google, meta, twitter, all have such massive captive audiences: their advertisers. Why not squeeze money from their actual customers that have so much of it compared to dubiously effective penny scraping from users? Are the major shareholders of these companies overleveraged in the advertising firms or something?

Except Google, who would presumably lose advertisers by increasing prices, and the advertisers themselves who now have to pay more.

What are they going to do, advertise on vimeo instead? There is no alternative to something like youtube.