Can confirm at least one tech news website argued this point and tore down their own video hosting servers in favor of using Youtube links/embeds. Old videos on tweakers.net are simply not accessible anymore, that content is gone now
This was well after HTML5 was widely supported. As a website owner myself, I don't understand what's so hard now that we can write 1 HTML tag and have an embedded video on the page. They made it sound like they need to employ an expensive developer to continuously work on improving this and fixing bugs whereas from my POV you're pretty much there with running ffmpeg at a few quality settings upon uploading (there are maybe 3 articles with a video per day, so any old server can handle this) and having a quality selector below the video. Can't imagine what about this would have changed in the past decade in a way that requires extra development work. At most you re-evaluate every 5 years which quality levels ffmpeg should generate and change an integer in a config file...
Alas, little as I understand it, this tiny amount of extra effort, even when the development and setup work is already in the past(!), is apparently indeed a driving force in centralizing to Youtube for for-profits