Some people here may have those Godly, fiber-optic internet connections, but I'm not one of them. I can upload 1 megabit per second, at max. A 360p video on YouTube has a bitrate of 1 megabit per second, and that's not including audio. At most, 240p would be the video quality everyone else would receive from me.
Have you ever watched a 240p video? It's awful.
And, that's assuming I'd be uploading to a dedicated server first, which inevitably generates lag. If it's not a dedicated server, then the bandwidth required is multiplied by the number of people watching. Since that number increases so rapidly, it's completely unreasonable to do it that way. But there's a problem with dedicated servers, too. There's at least 30 seconds to a minute, sometimes more, from the time the signal is transmitted, to the time the signal is received, because it must be interpreted by the server, first. Just that, in itself, completely invalidates the entire purpose.
But still, let's assume we can use a dedicated server without the lag. A 1080p video stream with audio is still going to cost over 8x the bandwidth that I have (
source).
And, that's provided that my CPU would be able to encode and compress the video in real time, without diminishing the quality significantly, on my end. I have a pretty quick CPU, but only the best of the best processors on the market can handle that sort of thing without screaming and crying.
Someone could do it, but not me.
But regardless, it's just not an efficient method, anyway. Even 1080p, when compressed, the video signal is hardly better than DVD quality... if it is even better than DVD quality. Most of the time, YouTube videos look like VHS quality, even in HD.
I know it sounds lame, but screen syncing really is the best method, and by no small margin.