Ads weren’t that much of a problem when they were contextual. I remember video game websites younger me used to visit having their background plastered with latest release by a AAA studio. This is contextual advertisement. It has no privacy concern.

The issue is that ads now are behavioural, privacy invasive and centralized. No matter what site you visit you’ll get unrelated, possibly scam, advertising that depends on a profile built by a large American corporation. It’s just not reasonable in this context to avoid using an ad blocker.

So yes, the problem is indeed Google (and Meta etc) who monopolized the advertising market. I would say the root cause is lack of antitrust enforcement.