There’s nothing inherently valuable to YouTube other than the fact that it’s the default video hosting website because it got there first. You can find other similar websites that provide video hosting that is equivalent, just without the massive audience YouTube has. Keep in mind your argument only works for G rated content because anything that is slightly controversial, even history based content, gets demonetized and there’s an entire other website called patreon that gained popularity because YouTube wasn’t paying its content creators for their work.

YouTube has lots of options for getting people to pay for their content. If they opt to pursue ad revenue they need to accept that a subset of their audience will use 3rd party apps to get around that. Most people don’t have ad blockers so it’s really only people smart enough to download the plugins. To me this is akin to Reddit pissing in the face of their users for the sake of maximizing profits. I get why they’re doing it, but for every trick they employ to get around ad blockers someone will come up with a workaround and I’ll just download that plugin each time.