Are all friendships meant to be forever?

Losing touch with friends seems to be a part of life, its not like we are still best friends with people we knew in first grade. I’m sure some of you are, but we become friends with people in life and then people move, we grow apart or we just lose contact. In either case why is it more difficult to get out of a bad friendship than a bad relationship? If you are in a bad relationship your friends will be the first to say you need to dump him/her and you can do so much better. But when you are in a bad friendship that is no longer beneficial to either party where are your friends to tell you that you can do better and that he/she has changed and you are better without them? Do we hold our friends at a higher standard than our significant others? Friendships are a type of a relationship so why should it be any different? As strange as it may sound, I definitely have some friendships from my past that were good while they lasted but I no longer talk to them or confide in them. It’s somewhat refreshing in the sense that you are not longer putting for the effort into something that isn’t growing. Much like a relationship all friendships can’t last forever, right?