I mean we already see the start of it with YouTube broadcasting Coachella, etc. More recently, Twitch has been used to stream gaming-related real life stuff, like the Dota 2 International 4 after-party DJ set. Conversely, the big media conglomorates are still wrestling with how to deliver content online and most just mirror your cable subscription to your device, rather than offer IP-exclusive methods of delivery.
I don't think Amazon is the best fit for Twitch - I personally would've preferred some company who is in the entertainment industry and more willing to start breaching into broadcasting live concerts, sport, big events, etc. on it. Valve, for example, already uses Twitch pretty heavily during their events and has shown interest to move outside of gaming (they sell non-gaming software via Steam) but they're probably also not mature enough to really start becoming a fully-fledged media company either. I don't really know of one company who is ideal in that space.
That said, I don't think Amazon is the worst either. It'll be intersting to see how they take it.