Item Sets Don't Carry Over

Hello, my name is Joey or KingSwaggins and I've been playing LOL for maybe 2-3 weeks. It has come to my attention that item sets don't carry over from system to system. For example, the item sets from my desktop don't carry over to my laptop. I believe that this should be implemented into the game because it would help out alot. Right now I have to put down all my item sets on my phone then copy them over to each system. It makes it very tedious and annoying. If runes and masteries carry over than so should item sets right?

Sincerely, KingSwaggins