What follows aren't particularly well-formed thoughts, just ideas floating around that I need to jot down so that I don't forget them. These are original (in the sense that I'm not copying these from anywhere that I'm aware of), but I'm not sure if they're unique or even valid ideas. I'd like to investigate them more in the near future. I'm admittedly lacking in both IP and Constitutional law education and experience, so there are probably glaring holes and errors in my argument. Take what you read here with a grain of salt.

• Section 8 of the US Constitution empowers Congress to enact Copyright protections in order to "promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries".
• This time-limited "exclusive right" is, in effect, a monopoly on said Writings and Discoveries with an expiration date attached.
• The DMCA further extends Copyright protections, making it illegal to reverse-engineer, re-implement, or otherwise circumvent a "Copyright-enforcing" mechanism.
• The Sherman Antitrust Act forbids companies with a monopoly in one market from using that monopoly to expand its powers into other markets. Illegal actions include:
  • Price fixing
  • Bid rigging
  • Market allocation/segmentation schemes
• Consider (for example) that a monopoly is not limited to the "only company X makes printers" case but can also be drawn along product-lines, such as "only company X makes $brand_name printers".
• Consider (for example) that by putting access restrictions on ink cartridges so that company X can control who makes and distributes ink for $brand_name printers, that company X is fixing prices and employing market allocation schemes. In doing so, it extends its $brand_name printer monopoloy to also include inks made for that printer.
• Lather, rinse, repeat for product/technology of choice (eg: DVD/CSS region encoding, eBooks, etc...)
• Hypothesize that exercising DMCA-protected vendor lock-in amounts to a violation of the Sherman Act, as it necessarily results in segmented-market oligopolies.
• Hypothesize that a "catch-22" exists. While it may be Constitutionally legal for Congress to forbid its citizenry from circumventing copy-protection schemes, it would be illegal for companies operating in the US to employ such schemes.
• Hypothesize that invoking the DMCA as defense of said schemes amounts to an admission of guilt with regards to Sherman.
• ...
• Profit???