User blog comment:ZanaLyrander/Thoughts on Legacy Skins/@comment-11157024-20130730114745

If you look at it from a bigger picture, Riot has (and should be) other ways where money can circulate aside from RP top-ups. Therefore, I think that legacy skins exist so that summoners may divert their attention to other things where Riot could still make a profit of. I hope this helps.