That sounds like a leading question for rhetorical purposes - is this something Google actually did, or are we speaking purely of hypotheticals here?

Note the solution I posed is something which Google already does on its search engine without calamity. Therefore I don't see a reason why it would fail for YouTube. In contrast the example you're giving seems pretty hard to just link to an authoritative source.

Put another way, I'm not advocating for Google to arbitrate the truth on a case by case basis. I'm advocating for Google to identify ahead of time which sources are well-researched and trustworthy, then outsource its fact-linking system to those sources.

If Google were to supply facts on a case by case basis that would be suspect. But that's not how the company operates, so I'm deeply skeptical they would become some kind of arbiter of truth.