I disagree. Many people have moved away from FB to IG after all the bad publicity FB has had. If IG was an independent company that consumer choice would mean something. As it is, any privacy conscious social network that mounts any threat to FB will simply be bought as happened with WhatsApp.
IG was like a 13 person company, do you think they would have successfully scaled without FB? Thats a pretty pretty big if. Had they not sold, its possible FB would have just murdered them.