I play Starcraft for the story only, and I loved it. Still play the campaign from time to time. I feel like a savage amongst civilized men on this thread.
I experienced both sides. First trying to become a professional CS:GO player, and after just having fun playing the Starcraft 2 story.
Some of my friends still deeply enjoy the competitive aspect. Sometimes I just want to see big stonking robots blow up aliens :)
The competitive scene has been stable and has kept sc going forever.