If you quit YouTube then you also quit all the content on YouTube that isn’t elsewhere. The best solution if you still want to use it is to use 3rd party apps. Personally I would actually count that as having no reliance on Google in particular anymore. If a video platform owned by Google wasn’t the most popular then it would be another platform. I don’t think you should think of 3rd party apps as YouTube frontends, but rather, apps that scrape videos hosted on Google’s servers.
I’d assume that using the service without paying (money or otherwise) for it would introduce costs to the provider hence being worse than not using it at all.
It still maintains their market position, which has value. For example, you might not visit other sites because they don’t have the content you want (and the content stays on YT because they have the viewers), or you might even share YT links to other people.
Technically I would not count as a user because content I see is being scraped and streamed separately.
As for content following the userbase, it stands true yet mostly for content that aims the most users by default.