Yes, there are costs to building your own platform, especially for video, but my guess is traffic is the main limitation. YouTube, Facebook, etc are trying to find things to put in front of people to entertain them, and if you can do well at this you can have an enormous audience. Streaming video from your own website to fans who care enough to seek it out gives you freedom but adds too much friction to seeing your stuff.
Yes, there are costs to building your own platform, especially for video, but my guess is traffic is the main limitation. YouTube, Facebook, etc are trying to find things to put in front of people to entertain them, and if you can do well at this you can have an enormous audience. Streaming video from your own website to fans who care enough to seek it out gives you freedom but adds too much friction to seeing your stuff.