Looking at Facebook's sign up page right now, and it seems that email is still required for registering a new account.
The thing is, almost every Internet service still requires an email address to sign up, and that ranges from mobile games to ecommerce shops. Some services provide the alternatives of allowing users to sign up via Facebook/Twitter/Google+; but in order for the users to get a Facebook/Twitter/Google+ account, they'll still need to sign up using an email address. Besides, almost all services that allow social network sign-in gives their users the option to sign up with email as well.
The services that do not allow email signups are few and far between -- like Medium.com, for example, but as said before, in order to get a Facebook or Twitter account, the user would still need an email address. Even mobile only apps like Whatsapp still appear to require an email address to sign up for their online support site.