Ads will definitely not disappear, only the tracking aspect. It will be more contextual ads probably, related to what page your are looking at, less related to you as an individual.
[1]: https://docs.google.com/presentation/d/1juu6UBguR7ru1Rhfyor9...
That is already a thing and there are already countermeasures: https://sponsor.ajay.app
Ads without tracking are an even less effective business model. We don't have to make ads stop working entirely, we just have to make them sufficiently ineffective that they're not worth paying enough to make ad revenue worthwhile.