It's an old saying, but it's true. If two friends have not talked for five years, it's neither of their faults, or both of their faults, depending on how you look at it. Friendship, like any type of relationship, contains two people and takes two people to make things work.
It amuses me to hear someone say "She hasn't called me in 2 years, I'm so upset, we're not friends anymore." Phones, e-mail, text messages, facebook, they are all two-way communication devices. If she hasn't called, and you haven't called, who is to blame? There isn't really a person to blame, unless you blame both parties equally.
It's easy to put the blame of a lost friendship on the other person, but before you do, please examine your efforts, or lack thereof, in the friendship.
Now, if one person is continually attempting to make contact, talk, go out, etc., and the other person isn't responsive, that is when blame can be placed. Otherwise, pick up the phone, and start the ball rolling on rekindling your friendships.
Life is a hectic, busy, thing, and I do wish I had more time to keep up with my friends from all walks of life. I'll have to try harder.