"An architect is a generalist, not a specialist" ..."An architect must know enough about each discipline to negotiate and synthesize competing demands while honoring the needs of the client and the integrity of the entire project." -Matthew Frederick

The design or the designer's ego is not the primary concern.  The success of the typical architecture project requires the cooperation of 5, 10, 20 or more people, companies, etc.  For one set of concerns to completely dominate the process is, in my book, probably a failure on some level.  A success for only one party is a success only for that one party.