Is sharing knowledge really desirable in a business?

A. Imagine a company where no knowledge is shared. Only information is passed on between employees within pre-defined operational processes. Each employee exchange information only to their immediate colleagues, either within their team/department or with the colleagues in the next/precedent levels in the operational chain. B. Imagine a company where all knowledge (tacit or explicit) is shared. All employees share their individual and collective (team/department) knowledge with every one else within the company. Each employee is free to share his/her knowledge with anyone else and to ask anyone for his/her knowledge on any subject (of a professional and non-confidential nature). My question is simple: which of these two extremes is likely to generate the most successful business, assuming they would be both in the same market(s) and every other parameters equal (eg. number of employees, age) ? I will expand on this question later on but for now, let me just say that for anyone answering B, please give me strong arguments because the majority of businesses today are still closer to extreme A.