That hasn't really changed though. He's just decided to manifest "Twitter is a video platform" into existence. The controls are still total ass though.
Yes just to be pedantic, twitter has never been "a video platform" – but that they've had support for streaming live events for years.
So take with that whatever it means, that it's just not going to be as first-class citizen like in Youtube. But the CDN etc must be good enough as those things are easier to do nowadays.
Looking at the SpaceX feed, they seem to be using whatever tech they got from the Periscope acquisition (at least the servers were still pscp.tv).