Marvel Comics:

In late 1994, Marvel acquired the comic book distributor Heroes World Distribution to use as its own exclusive distributor. As the industry's other major publishers made exclusive distribution deals with other companies, the ripple effect resulted in the survival of only one other major distributor in North America, Diamond Comic Distributors Inc. In early 1997, when Marvel's Heroes World endeavor failed, Diamond also forged an exclusive deal with Marvel—giving the company its own section of its comics catalog Previews.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". The failure of what high profile business initiative caused Marvel to approach Diamond?
Marvel's Heroes World