the featured games

What are the odds that the other game modes can or will get featured? I mean normally there are 5 ranked SR matches that you can choose to spectate but just now i saw a featured howling abyss game. My question is what about the other two modes? Why do we not see featured TT or DOM games? Is it that they are featured but I'm not looking at the right times, that Elo is not high enough to be chosen as featured or is it a conscious decision that Riot made? If the former then great I'll just move along. If it is the second then something is very wrong with the popularity and presentation if the newest game mode has Elo potentially high enough to be featured and 2 game modes that date years older don't. If the latter why is a totally for fun game mode given higher priority than ranked TT? Something seems off about this.