Differences between the various parts of an organisation are meaningful. Variety is the result of specialisation and focus in customer segments, abilities and expertise, capital expenditure, profit centers, responsibilities, products, geographic coverage, etc. There are numerous ways to divide and manage. Designing the parts and their boundaries is an important element of organisational design.
Without differences there is little use in bundling the different(?) activities in any form of organisation. The added value of any organisation exist because of the differences. Even in the most loosely coupled form, there is some kind of specialisation. On the other hand a collections of specialised elements without any of form of unity and mutual benefit is not very efficient. Recent actions among investors to demand splitting (listed) organisations into separate, more valuable parts is a proof of that point.
The balance between benefits of specialisation and the added value of unity is delicate one. Traditional trade-offs become obsolete with the connectivity made possible with modern technology and the current and reliable transport, transaction and juridical systems.
The analogy of ton sur ton might be useful and inspirational. Ton sur ton is a delicate colour scheme of adjoining colors. Within a base colour there is a large variety of shades. The differences in shade allow all kinds of accents and nuances, while there is a clear relationship between the elements. The ton sur ton principle prevent clashing colours.
While savouring the variations of expertise and focus, many organisations also want a common element (colour) that characterises their identity. Choosing the right palette of colours and mixing a wide variety of shades is an art and requires skills and knowledge. Is management any different?