Not sure what riot game you are pointing to but if it is a fps game,those games are a class on their own they dont follow traditional rules. You can see it in the vieuwer numbers on twitch. Fps games have far more vieuwers then any other game type out there.
Skins dont make enough,they tried that. And i can see why skins are not enough in BG,and that is because optics in this game are not important. The community isnt big enough to get a lot of satisfaction from a skin that in the end is rather cheap to get and not all that rare. They dont have the same amount of apeal that special skins have in fps games,for a variety of reasons. The game itself is just to small for that probably.