League of Legend's UI

I see Riot selling skins, ward skins, Icons etc but how come Riot doesn't sell in-game UI boarders like you see on streams. I get that you can get the custom UI boarders for free and install them but you can also get free custom skins and install them and yet Riot still sells skins.

I wish there was a Buy UI boarder option and then I can switch inbetween them as I feel instead of having to install and unistall over and over again the ones I feel like using.

I think Riot should also sell loading screen boarders. Keep silver/gold/plat Etc boarders but have different boarders you can buy.