Disney may lose exclusive rights to Mickey Mouse by 2024

That's copyright longevity, expanded in 1998 by Congress to the lifetime of the creator (Walt Disney) plus another seventy years. Which means Steamboat Willie will enter the public domain. Mickey Mouse the character is not only copyrighted, but trademarked as well. And trademarks endure for the length that the Walt Disney Company remains solvent. The whole shootin' match has to be kaput before Mickey Mouse can fall into another entity's hands.

There's a distinct difference between copyright and trademark. Copyright applies to the cartoons, which are works of fiction, that are protected for the lifetime of the creator, plus seventy years. It was originally 28 years after the Revolutionary War, regardless whether the creator was alive or dead. So all the old Paramount Popeye cartoons are public domain, as are the Betty Boop, Tom and Jerry (later renamed to Dick and Larry) cartoons ... any cartoon on those cheapie collection discs is public domain, so the cheapie publishers can circulate them without penalty. Trademark is different: the character is elevated to a symbol for the company that developed it, so like a corporate logo, there is no expiration date on it. As long as the company that owns the character is solvent, that character is legally regarded as their property for life. Thus, Popeye the Sailor Man is a trademark of King Features Syndicate, and cannot become public domain until King Features dissolves in bankruptcy (and somehow nobody buys their trademark character). Some Bugs Bunny cartoons have slipped into the public domain, but Bugs Bunny himself is a trademark of Warner Media, so they still have that rascally rabbit locked down tight.