Marvel might not be making any money on all their books. They could be taking a hit (or just breaking even) on their MANY miniseries in a concerted effort to control market share and hurt the competition.
I'm sorry but that's just ridiculous. How many series have they axed that fans absolutely loved because they weren't selling? Many. I'm sure being the leader in the industry (usually) is a nice feather in their cap, but they're first and foremost a business.