Let's also keep in mind plenty of people still carry s4 and s3s today as well so people may not be upgrading as usual.
Also it's hard to different Android, how would Samsung go about that? I think they done enough, their own app store fitness apps, they try hard to pretty it up, try hard to be different from all the other android makers. Outside of maybe a iTunes equal and a easier backup method for noobs I don't know what they can do at all.
With the older models still selling and Samsung using android I think they need to cut back big time. Lose the alpha and all that stuff bring out the 6 and nite and kill the rest.