They didn't do it because they had a monopoly, they don't have a monopoly. It was more base than that. They did it because they wanted more money. Which is their right. I'm not complaining, but everyone's putting forth a great deal of high tone reasoning fro something that really is base venality at its root. They want more money. They believe they can get it even though they are not a monopoly. Even though Facebook is bigger. And even though their users will get mad.
The reality is, most of their customers aren't going anywhere. Consider all the times you use Youtube. Trying to find a music video, watching sports highlights, videos from your favourite creators. Can you switch to DailyMotion for all of that now? Are all of your creators posting their videos on Facebook? Even if they are, are the videos as easy to find and discover as they are on Youtube? For content creators, is there anywhere else they can share and expect to find the same kind of audience? Not really.
This is what I'm talking about when I say monopoly. It's true, there's other options. A creator can post their videos on Vimeo and host their own website to monetize, just like someone could have taken a horse and buggy instead of the new railroad. No one is forced to go by train, but doing it the old way is inefficient and expensive. n both cases they won't get the same bang for their buck.
I just become worried when they use their monopoly to extract as much value as possible, far beyond what they need to sustain their profits. I think monopolies are bad in principle, and Youtube is another example, just like Microsoft was, cable companies are, telecom was, railroads were, etc.
But I'm not sure that's clear. There's been a distinct increase in the number of in-video ads (Raycon, Skillshare, ExpressVPN, Squarespace, Curiosity Stream, and so on), which probably corresponds to a distinct decrease in Youtube enabled ads. So with that logic, Youtube is probably making less money from top creators, who have been skipping the middleman entirely. This seems more like a step to retaining existing profits instead of increasing them.
Perhaps their current pricing model is fair, I have no idea. But being the de facto video hosting site gives them tons of power. They have the ability to extract extra value out of their users---much more than a non-monopolized market would allow.