Websites that do not use ads cannot survive (on a large scale) if their competition uses ads.
Large consumer-facing websites are forced to use ads.
As long as ads are legal, consumers will not have the choice to use ad-free websites. (The only exceptions being startups operating at a loss.)
This is not even solved by websites allowing for paid, ad-free plans.
Who pays for Google? You, when you by a can of Coke. Coca Cola increases the price of the drink, then gives that extra money to Google.
If you are using a paid, ad-free plan, you are not only paying for the plan, you are also still paying the increased price of Coca Cola.
As long as ads are legal, people who use paid plans have to pay more* than twice of what the service is actually worth.
*Don't forget the effort that is being put into designing ads, building tracking technology, managing tracking data centers, which again, are paid by you, every time you buy anything.