I think nonrelated friends can reach the level of commitment that we expect from family but I do think saying a close friend is like family has become grossly overused. It is like when people say their dog means as much to them as a child. Yes you love your dog but talk to someone who has lost a child and tell me losing your dog affect you like that. A good friend of mine lost his son twenty years ago and his wife is still a grief support group and still set his birthday to be with close friends and talk about him. I don't really like my brother but if he needed money for a heart transplant I would sell my house to pay for it, bail not so much.
We have always built and chosen family to some degree. Even though me and my wife are both half hillbilly we are not blood related but she as my family. The man who raised me is not related to me by blood and I don't call him dad but he is my father and I am his son. I consider my brother-in-law's kids to be just as much my nieces as my brother's kids are. I don't have any friends that I would put in front of closest family even though I like them better than most of my family.
Humans are tribal and family is just what we call those in our smallest and most trusted sub-tribe. Typically is close blood relatives and our mate's close blood relatives but people who don't have those close relations either because the dies or through estrangement form bonds with other people that are just as close. My next-door neighbor was ostracized from his family because he is gay but when he fell and broke his the group of people who came and took care of him and his house for months are family.