> Out of four hours you get about 10 minutes of meaningful detail about the incident

Most documentaries have always been very low on information density. Even universally loved ones like something from David Attenborough are mostly a collection of disconnected (yet amazing) film snippets with a bit of commentary over the top. It's only gotten worse as narrative has become more of the focus.

There are exceptions, but when it comes to conveying meaningful information and detailed analysis youtube is far superior than mainstream documentaries.