A stupid question that may be, but ....

why none of those AEN companies has monthly rebilling for regular members? For instance, $ 14 a month or $ 19 or whatever....

They all have rebills only for gold or platinum stuff, but when you actually look at it, regular members get also at least some 20-30 new galleries daily, which makes it sort of unfair that they should pay only once for whole year... and ofcourse, there's also rebills in my pocket (or any other webmaster)

Is there an obvious reason for this that I can not see?