The heart of every software company is the development department.

Without it:
- The sellers would have nothing to sell
- Testers won't have anything to test
- Technical support wouldn't have anything to install

As much as I would like to agree with you. It always comes from both sides.

Without sales we wouldn't have clients to program for.
Without testers we couldn't test our software so thoroughly. (We can't discover all bugs ourselves)
Without technical support we would have to handle tickets ourselves; meaning no time to program.