No, comic books just don't sell that well. However, I believe the main purpose of these books is marketing the more expensive projects (toys/tv/movies).
Sales usually seem to follow a similar pattern to what I wrote below:
MainBook1: 150K, MainBook2: 60Km, MainBook3-10: 40K, MainBook11-25:30K, by this time they do a new number One and cycle starts over.
SideBook1: 70K, SideBook2: 30K, SideBook3: 25K, SideBook10-12: 15K
So while a book like Way of X and SWORD may not last too long, if they are well written throughout, they will still make a big impact (even if sales are low).