I read an article somewhere about the problem with streaming live sports. The biggest issue is that it's highly regional and for these streaming companies to get Netflix-size subscription numbers, they need global content. So sports streaming involves high costs and only offers regional subscription increases. Their conclusion was that barring some fundamental changes, sports will not be a major draw.
It kinda makes sense too. Outside of global events like the Olympics, sports are regional. If they get the license for NFL, they can increase US subscription numbers, but that won't translate to global subscriptions. Likewise, if they license a European football league, that will increase European subscriptions, but may not even translate to other soccer playing regions.