I think a good analogy would be a large cafeteria which has its own farm to grow produce. You may think this vertical integration is a great idea because you feel the cafeteria can save paying retail prices for its food and could therefore undercut other cafeterias. However the reality is that most large cafeterias would typically buy their food wholesale or at least in bulk and they wouldn't typically head out to the supermarket to buy all of their ingredients at retail prices. The synergies which initially appear to be there by 'growing your own' aren't really there.