Which lasts until the advertisers figure out that the views are going to toddlers watching creepy videos featuring unlicensed Disney IP and bad Peppa Pig creepypastas, and the party ends.
Nope. In that case YouTube is just forced to adjust their targeting - they're simply showing the wrong ads!
As another comment already correctly stated: kids do have indirect spending power by being able to manipulate the spending of their parents. This works particularly well with the kind of parent that uses YouTube as an easy and reliable pacifier - this kind of parent will most likely also take the easy way out of the situation of an obnoxious kid screaming and blaring about it's dire need for product X (as seen on YouTube), which means buying the product so the goddamn kid shuts up.
Advertising is not immune from market corrections. The whole "pivot to video" trend was a market corrections to ad rates, _and_ has died off in a response to another market correction.
Of course it's a naive statement on its own. I mean only to enforce the fact that YouTube's advertising stance is predatory and has been since day one.