Taiko isn't an intuitive mode, mainly because Taiko was meant to be played with drums and two sticks, there is also the ugl- unsightly default skin that pushed many people away, the original TNT skin is more colorful and animated. Another reason I believe newbies can't get into Taiko is the lack of a default tutorial beatmap. Standard has a tutorial when you install osu! and mania doesn't really need one because it's much more intuitive and there're a lot of similar rhythm games in the west so it's easy to guess how to play. CTB is a very intuitive game mode too, there're many arcade games using the same gameplay concept, I can remember at least a couple of them from the arcade where I used to play in the past, not much guessing needed.