Final answer:
The choice not identified by the authors as a reason why organizations enter into partnerships with each other is increased competition. Partnerships are typically formed to reduce costs, access new markets, and share risks and rewards, not to increase competition.
Step-by-step explanation:
The reason for organizations entering into partnership arrangements with each other that was NOT identified by the authors is increased competition. Typically, partnerships are formed for various strategic business reasons, which often include cost reduction, access to new markets, and sharing of risks and rewards. Partnerships can facilitate cost-sharing, leverage synergies, and help businesses to expand their market presence more efficiently. Additionally, shared risks are a significant factor; partners can pool resources to mitigate individual risks associated with business ventures.
On the other hand, increased competition usually has the opposite effect, as it can reduce a business's profits and may even result in businesses being driven out of the marketplace. Therefore, it is not commonly a reason for forming partnerships but rather a challenge that businesses strive to manage through other means, such as forming associations to benefit from shared advocacy and influence on regulatory matters.