It Just a Different Interest Now!
In the course of our life, many people come and go, and that is part of the life that we live in. There is nothing to be worried about because it is very much natural, as long as you don't let it go because you messed up big time. Otherwise, it will be your fault for ruining the friendship.
If the connection is lost because we are heading in a different direction, or not living close enough, then it is still ok. We have to get used to it, and there is nothing much you can do. Don't blame yourself for not doing your best to keep the relationship, but be grateful that you have not destroyed the bridge, since if the conditions are right, you can reconnect once again.
The main thing is that we have a different interest, different priorities, and different directions, which are mainly caused by different situations in one's life. those factors can really be one of the main reasons why we could not make a good connections like we used to, or maybe the reason why we don't have enough time to hang out like we used to be. So enjoy it, follow the flow, and don't over think, trying to find the reason the friendship are fading away.