The problem with ads is not a few ads here and there, it's how it negatively impacts every interaction with those sites:

• ads that load in later than the rest of the page, because they first need to finish the auction of who gets to show their ads... And bam I again missklicked the link because the whole fucking page got shiftet down a notch
• needing a short guide how to do something? Yeah first look at these five (5!) ads which are longer than the guide you want to watch, except... The freaking algorithm favors long videos, so the 30 second guides get padded to over 10min...(with more ads inbetween)
• these ads we show you, yeah they might contain some java script... So you screen them, correct?... Nonono, we can't do that at this scale!
• hey google where can I download this free tool?... Here is a list with download links... Ehh, the first five are ads and lead to some crazy scam site. Don't you check what you deliver as ads.?.... Nonono we can't do that at this scale
• look at this ad for this shady mobile again for the 25ths time today... But youtube that game doesn't look at all like in this ad!.... Thanks for your report... Here's the same fucking ad again!

There was also a report recently that google also screwed their customers (those companies who pay for the ads) where google showed ads as in-stream ads in some auto-running videos in the background.

The whole industey is just broken. Present me with non-intrusive, static ads served from your own site and nobody bats an eye (also ad blockers are a non-issue then)