Google's cost is not simply distribution but also what's needed to support its advertising; the surveillance of keeping track of who you are, what you want, and when, and the bidding system so it can sell advertising.
If content creators pay Google to distribute, that wouldn't pay for the surveillance/sales infrastructure, and it would take away the advertising profit center.
There's no business reason for Google to change unless the creators also pay at least as much as the expected advertising profits, fully amortized.
If they do that, then it'll almost certainly be cheaper to host elsewhere.