Advertisements distort the market arrangement. When one uses advertisements to generate revenue, it inherently creates a situation where the advertisers are the actual customers. This incentivizes the site toward the needs of the advertisers instead of the users in any situation where those needs don't align.

So yes, eventually it would be the end of the world. Within a decade or two the site would go to hell. We're seeing it already with most ad based sites. People are complaining Google is getting bad. We already know that Reddit is. That's why most of us are here. News sites go to shit, when they distort themselves for advertisers. Example after example of advertising, making site after site worse over time.

The advertising model, is the original sin of the internet.
We need to find another way.