Why does the entire group need a Value Proposition?

To me, value proposition is always based on a specific service or product. Why does the entire group, like Microsoft, need a specific Value Proposition? Is the company with different business is multitasking?


Reference: the explanation of Value Proposition from Wikipedia

A value proposition is a promise of value to be delivered and acknowledged and a belief from the customer that value will be appealed and experienced. A value proposition can apply to an entire organization, or parts thereof, or customer accounts, or products or services.

Creating a value proposition is a part of business strategy. Kaplan and Norton say "Strategy is based on a differentiated customer value proposition. Satisfying customers is the source of sustainable value creation."[1]

Developing a value proposition is based on a review and analysis of the benefits, costs and value that an organization can deliver to its customers, prospective customers, and other constituent groups within and outside the organization. It is also a positioning of value, where Value = Benefits - Cost (cost includes economic risk).[2]

I think the reason that every profucy needs a value proposition is no single product can satisfy everyone. As our life quality keeps increasing, people have higher standards towards the products they use. For example, even a product that almost every needs--- milk, is diversified into various kinds such as different flavours, low fat, and high calcium to meet the needs of different group. In order to survive in this competitive market, companies need to do everything they can to grab the eyeballs of consumers and develop them into a loyal client group. Therefore, it is extremely important to understand what the clients really need. This is the base of value proposition.
In fact, it is kind of like the meaning of life that one must be clear of who they are and what they pursuit to live a happy, meaningful life.