Why is it so hard to find long term friends?

I recently went through the worse friendship breakup of someone who I known for a long time. I thought our friendship would go places, but she didn't once care to be friends with me that long and din't take into consideration my feelings either. We came from the same generation, same age, same history, but different backgrounds. You'd need it'd be all fantasies and wonderlands like they share in the movies, but it's worse in real life. How come people just don't give an f when the epidemic of loneliness is so bad right now?