Why does everything have to be a conspiracy?
A lot of advertisers moved away from Youtube and Google as a whole due to there adverts being shown (accidentally) on videos that were promoting terroism. It was all over the news in the UK. It has nothing to do with Youtube finding a solution. Advertisers have already lost faith.
Add that to the increase in people using adblockers (which obviously means less revenue for google and the advertisers) and there's your reasons.