I think that the prices are a bit too high myself. But as long as the champions can be obtained by playing I don't care too much. Cosmetics can be as high as they want this means only that the quality threshold to which the purchase will be worth it is higher, meaning one will buy less stuff.
I kinda "welcome" high prices for skins in a sense, if they were lower I would probably end up spending MUCH more that I would spend with higher prices