I think the reason for this is that ads don't exist to inform consumers about things they might want to purchase. Instead, advertisers have learned to manipulate viewers to create desire for their products. The effectiveness of ads is almost entirely non-rational. Watching ads is effectively watching corporate propaganda, in many different degrees of harmfulness.
I'm admittedly an idealist. But something seems amiss to me when the supposed only way to pay for journalism (which exists to inform the public) is to embed advertisements (which exist to misinform the public).
This isn't true. Advertisers pay to access a target audience, because publishers control that access and their business model depends on their ability to monetize it. In general adverts are not unwanted. In fact, some consumers even request companies to send them adverts intentionally, and even subscribe to marketing publications.
Heck, some consumers even pay to subscribe to catalogues.
In general, web adverts are disliked because they are very intrusive and degrade the performance of a website, and in some cases expose content that is socially frowned upon.
Try this: all is paid for by advertisers, it has always been. Deduce which of your "exist to" beliefs is mistaken - perhaps due to advertising about it ...
No. There have always been websites by people who just want to share with the world, and paid services, and useful government programs, and nonprofits (go on, find an ad on https://www.gnu.org/). Your belief is mistaken.