The Los Angeles Times has an interesting article at this link that discusses the WWE Network launching as an over-the-top service rather than as a traditional cable network or pay channel model similar to HBO.
Vince McMahon is quoted by the publication, explaining that WWE had deals with major distributors for a network that would have generated fees of $0.20 per month per subscriber. However, much to "the chagrin" of his staff, McMahon told them he wouldn't sign it.
Instead, WWE ultimately determined that an over-the-top service gave them more control and a better user interface. Vince is also quoted in the piece, saying what pay-TV distributors wanted in return for the WWE Network was "too restrictive."
The company has spent more than $40 million in WWE Network development in a process that has been about five years long. You can read the LA Times piece in its entirety at this link.