A young, growing company has finite resources and will therefore achieve competitive advantage when playing for limited, explicit gains in a marketplace of its own choosing. Specialization breeds an organization sensitive to opportunities and quick to act.
But any advantage withers if follow through is weak. It will be weak if resources are dissipated. Resource dilution is a sure formula for mediocrity, a state of being that aspiring growth businesses cannot afford.
Steve Jobs started in a garage and built the most valuable company in the country by saying "No!". The bottom line is that you can't do everything, so choose wisely.