> Maybe people just got fed up with Youtube.

Creators are not reporting any declines in ad revenue that match the drop in view count. Indeed several have reported revenue is the same despite the view count drop. So it's quite unlikely people are fed up with youtube in any meaningful way.

The people using ad-blockers were not watching ads, so it would not make a difference to revenue streams. If anything, profit would go up because Youtube server capacity is not being used as much by ad-block users.