Last year the initial event of the "adpocalypse" happened, which both demonetized a lot of channels, and at the same time roughly halved what advertisers were willing to pay, even for complying channels. Since then a few additional waves of demonetization happened.

Every time Youtube demonetizes a creator they are also demonetizing themselves. The combined effect of all that could have held back profitability significantly, especially considering that they are shooting for comparatively low-margin advertising business model compared to other platforms.