Buying runes and getting 10 cents on the dollar back just makes me realize I shouldn't buy things

Whenever they change up some skin I love (hyena WW into big twitch) or they offer 30 cents on the dollar for ip runes, I realize I shouldn't be spending money on content in the game because they can just as easily make it obsolete or turn it into something I dislike later on. I don't see why my content depreciates but sales on skins never does.