You’re thinking of trademarks, which require an ongoing usage in order to maintain.

Copyright and patent have limited terms in order to achieve their intended purpose, which is to advance the arts. If you create something new, you get a monopoly on using it for a limited time. If you want to keep selling your art after that time, you have to make new art. This was more obvious when the copyright term was 14 years. Thanks in part to Disney, it’s now become so long that I think it has the opposite effect. Big creators know they will have such a long monopoly–the lifetime of the author plus seventy more years–the incentive isn’t to make new art, but to reuse existing art. Fuck Disney.