One will argue that 'e-sports' already peaked in 2002.
Not that I'm saying the market won't grow - on the contrary, I think it will continue to do so. It's a very small market compared to sports generally ($1 billion would barely buy you a top class sports team, let alone a network like ESPN).
Much as I don't play football anymore but still watch it, I also follow some games :) and so do many friends in their late 30s / 40s with families (mostly the same ones as others in the thread, like Magic: The Gathering, League of Legends, Hearthstone, etc.).
Famous last words.