It could be coming. Facebook is supposedly interested in blockchain technology. It will be interesting, if they do end up creating their own coin, how long it will take them to do it, and whether or not it will be too late. Huge corporations with many moving parts and people with varying vested interests don't often move on things very quickly. Will they see the value and inevitability of the attention economy before the masses flee for STEEM or something else? I'm doubtful, but who knows. Maybe they'll be more nimble than I think.