I think you're confuning centralization with a walled garden. Because if what you said were true, then why would Disney be buying Hulu?

The larger of a content creator I am, the more I want to control distribution.

Having my content on a site with someone else's rules sucks, because I am at their mercy.

For example, with Disney owning Hulu, they can tell Google to go F-off, and never worry about their content being accidentally censored, deleted, etc.

For a smaller content producer, the value might even be more significant, even if the dollars are less.