This argument against vertical integration sounds a lot like United States v Paramount Pictures, inc [0], which forced Hollywood to end the vertical integration of the “studio system” [1].

Honestly, I’ve wondered if Apple has deferred manufacturing to Foxconn et. al. just to avoid being ruled a (vertical) monopoly with this precedent.

[0]: https://en.m.wikipedia.org/wiki/United_States_v._Paramount_P.... [1]: https://en.m.wikipedia.org/wiki/Studio_system