I believe steemit already is the next big player in social media.....that is obvious by the growth.
Facebook won't be going anywhere though, because of what you said about it being a great way to connect with family and friends. I for one was able to track down my sister - after many years of having no way to reach each other, locate and adopt both of my dogs, and reconnect with a close friend after moving out of state, ALL because of Facebook. And I know that there are countless stories out there just like mine. So I for one, don't want to see Facebook go away.
I never saw steemit and Facebook in competition with each other anyway.
Facebook is more for entertainment, steemit challenges people to contribute quality material, which in turn can educate, inform, and empower the community.
EUREKA! I just gave MYSELF a great idea for my next blog!
Thanks @inboundinken