You can use Youtube as a producer, or a consumer (or both). You are right that as a consumer, you are part of a captive audience. But as a producer, the others

You can use Youtube as a producer, or a consumer (or both). You are right that as a consumer, you are part of a captive audience. But as a producer, the others might be a good alternative - especially if you are not trying to monetize and/or rely on YouTube recommendation to get discovered. If you're posting family videos for aunt Mildred, and an instructional video linked to your blog post - then there are perfectly fine alternatives to YouTube - of which most people are completely unaware.