The "subscription-based websites" model is for sure a thing in a lot of areas (eg. Kagi search engine) but it's only for niches, most of the people want and will be on "free" websites.
On a more serious note, I don't think the ad monetization model will ever die. It's the simple principle of supply and demand; as long as there is a demand for a free experience, it will be profitable to provide an ad-supported version. It's why YouTube cranks out billions in ad revenue every year, even if they have a slightly insidious monetization model. This is what the free market settled on, and it's competitive enough to push both ad-based and subscription-based monetization to compete harder.
My view on the topic: https://blog.kagi.com/age-pagerank-over
But things seem to be shifting towards "influencer ads" at the moment. And I think there is some merit to the web ad inflation accusations.