steam stats are still a good measure for tendencies. far better that your stats anyway.
A possible point being that the *tendency* could be towards more and more people gradually switching over to just running Elite from the launcher without ever opening steam. (Although in all honesty I suspect that the player hours for steam are more likely to be OVER inflated since steam will log you as "playing" even if you quit the game but forget to close the launcher, which I personally do all the time.)