a) starting from .99 doesn't mean 0.99 but way more. In fact, most channels are in the 3/5$ range for weak content. You can have a pack of documentary and soap just for 35$ or take it for free in your TV.
b) who needs Youtube paid channels? The same content is available elsewhere in Youtube (maybe flipped horizontally to skip filters) :-)
c) are you sure this is not the next Google's cancelled service due to weak response of the users?