The motivation is obvious when you look at it from youtube's perspective. They do not value content creators much, but they lick the boots of advertisers. They want to create a system that is as smooth for advertisers as possible, regardless of the impact on any other aspect of the platform. They want to reduce the risk of bad PR (which causes advertisers to run away). All they care about is the product of eyeball counts and ad impressions yielding dollars, they don't understand at all the goose that lays the golden egg or how easy it is to kill it.