Why are my friends so flakey ?

Ok ..I have noticed that for the past few years ...some of my best and oldest friends / relationships have been ending due to them being so distant and flakey ..I mean I have known some of these friends for decades and they are so flakey I have decided to leave them alone ...I think your suppose to show your self friendly if you want to be and remain friends ...But why is it that it seems people are so careless and flakey lately ? Anyone else notice this ? OR is it just me?