Agree and disagree with the analysis. I think you're right on the streaming piece, compared to games like LoL/DotA/CS:GO. Streaming is the way games get popular now. Though there is some nuance to the vehicle of marketing.
I don't think you're quite on the mark with the competitive spectator appeal as a sport becoming the appeal of gaming. I think a lot of people over emphasize the impact that "eSports" has had on shaping game design. In fact, most games that are designed largely with this aspect in mind have failed miserably.
The reason why is when this new eSports/competitive game comes out, big streamers are going to have growing pains learning it and that isn't fun for viewers to watch so the game will be avoided. Nobody wants to watch say Lirik or whoever fail at DotA 2 all day. But he can hop into some indie game or AAA title with a high skill floor and pick it up quickly and rather than focus all of their energy on learning the game can balance entertaining the stream and exploring the game.
The free to play aspect is also important, that's a virtual requirement if you're looking to be a top chart popularity game now, there is just so much competition it's hard to justify dropping $30 on a game without having played it for a while.
None of these titles are particularly interesting to watch for me because the strategic value is nil, it's basically a combination of mechanics and luck, but that makes for a good formula for mass market appeal so I guess I understand the dominance these titles are having.