That's the vertical integration aspect - if they own each step in the process, they can avoid supply shocks and have a more efficient business. It is also a consolidation of power which can create risks for consumers, though. As explained by 30 Rock:
Jack: “Imagine that your favorite corn chip manufacturer also owned the number one diarrhea medication.”
Liz: “That’d be great, because then they could put a little sample of the medicine in each bag.”
Jack: “Keep thinking.”
Liz: “Except then, they might be tempted to make the corn chips give you –”
Jack: “Vertical integration.”
In this case, JLC could decide to steer their customers towards copycat parts which they have a commercial interest in, knowing that the marginal cost of doing your own assembly or switching providers would be fairly high.
I figure there's tyo opportunities to steer design decisions:
* When the schematic is being developed
* When the order picking is being prepped.
The second choice is an easy win for them, but probably limited to near-commodity parts-- I don't care which brand of 330 ohm resistor I use, as long as it fits the footprint. I'm not sure if there's that much margin though-- unless you're swapping out some absurd diamond-plated milspec parts, how much kickback can you fit?
The first choice seems the more lucrative one, but it may be off-limits for a lot of hobbyist and short-run products though. You'd have to tap into the design life cycle very early, and I suspect that's not as widely available as you'd think. A lot of projects still come out of things like datasheet reference implementations, canned designs, or transcribing a prototype breadboard, and these customers would need a lot more than a marginally lower price to resolve the risk factor of swapping parts out.
