Are game endings becoming less important?

So i was running through my steam library just now and i realised that i had hardly completed any of the games in the list. When i first started gaming I’d retry levels, re-load or just persevere for hours if not days just to complete games or see all the endings (Dune 2, C&C and Deus Ex come to mind) These days my attention span is shorter and my life more crowded so i rarely finish a game. That’s not to say i don't enjoy them its just there seem to be more games coming in and less time to play them. I'm curious as to whether this is a sign of my age - 31 :( - or it’s a change in how people play games in general and if the latter is true is it a sign the rise of mobile and casual games has eaten away at our appetite for a getting to the end of a good story.