Sales and services are conceptually distinct activities different from software development, and therefore need to be in a different entity with different fundamental rules of engagement, i.e., a profit motive. Marketers don't have the ethical and moral imperatives that are placed on the developers.
(See e.g. The Declaration of Software Freedom and Explanation, Free Software Foundation, and the `Definition of Free Software'.)
Marketers need to be controlled by the community of developers. They should not be in a position to control the creative community of developers, as is the case with proprietary software. With the software licensed under the GPL, the developers cannot lose control of its marketing; for even if outsiders gain control of the first marketing company, developers can repeat the process with a new marketing company. The resultant ownership of the marketing company by FreeDevelopers depends on how much of the marketing company is shared with hardware companies. Also it depends upon how many proprietary software companies are taken-over to free the code and their developers, as opposed to re-writing their software from scratch. Ownership in the FSMC by FreeDevelopers can be replenished by fresh yearly stock options to FreeDevelopers to ensure that it remains a majority-owned subsidiary of FreeDevelopers. Marketers need to coordinate with hardware companies to produce a joint solution for customers. Public Investors

Developers' power needs to be aligned with market power. Proprietary software companies use the financial markets to control the natural power of developers, by paying them to close the code, and thereby divide and subjugate the developer community. Investors are allies, because they are rational utilitarians who will back any entity that will benefit them, without emotional attachment to current market leaders. The marketing arm of FreeDevelopers must align developer power with market power and give a place for investors; otherwise the financial markets will resist the new commercial structure and try to perpetuate the current proprietary model. Joint Venture/Hardware

The customer wants a joint software/hardware solution, because computers are necessarily a joint product between hardware companies and software developers. Hardware and software are co-equals and therefore need to joint venture in delivering solutions to customers. History has shown that while separating software and hardware into core competencies is a more efficient solution, they still need to work together on joint production. Customers

These are the same traditional customers of computing solutions.