I'm pretty sure ad revenue for most channels is negligible so they resort to third party sponsorships or platforms like Patreon. The advertisements are there for Google to recoup some of the cost of running YT.
not sure what your point is. let's assume it's true. That still means the ads are paying for YouTube to host the videos. Without that those channels would have to pay for hosting themselves and could not afford to make the content.
Further, most of them would have never even tried if it wasn't free to start
Then, I don't buy your premise. Most of the channels I watch insert ads directly for Brilliant, NordVPN, etc... which means even without YouTube's ads they're still ad driven
> Most of the channels I watch insert ads directly
Those are third party sponsorships done by channel owners, not ads inserted by YT.
> That still means the ads are paying for YouTube to host the videos
Your assertion was related to the channels themselves existing, not YT as a platform. I can agree that the platform probably wouldn't exist without some sort of funding source but that doesn't necessarily need to come from ads.