Unfortunately, the inapplicability of intellectual property doesn't seem to matter much. They probably wouldn't use an expired patent in a suit, but many of these places just make minor tweaks and file for a new patent on the "new invention". There's enough grey area that you have to go to court to hash out whether or not the technology is infringing.
Opposing IP lawyers working for one of the largest media companies in the world have openly told an associate that while the thing they C&D'd her on may have had a good chance to be ruled non-infringing, she should comply with the C&D anyway since she would be financially ruined by a lawsuit, win or lose (realistically, she wouldn't be able to win because she'd run out of money WAY before the case even approached a conclusion -- one of big companies' favorite strategies is to "starve out" their legal opponents by making the case as expensive and convoluted as possible).
Opposing IP lawyers working for one of the largest media companies in the world have openly told an associate that while the thing they C&D'd her on may have had a good chance to be ruled non-infringing, she should comply with the C&D anyway since she would be financially ruined by a lawsuit, win or lose (realistically, she wouldn't be able to win because she'd run out of money WAY before the case even approached a conclusion -- one of big companies' favorite strategies is to "starve out" their legal opponents by making the case as expensive and convoluted as possible).