Trademarks require enforcement (as others have noted), copyrights do not.

There is the doctrine of laches which might be applied in general to an excessive delay in asserting an equitable right, but there is no failure-of-defence loss of copyright under US or generally Berne Convention statutes globally. I've most frequently seen laches raised in the context of patent enforcement. <https://www.law.cornell.edu/wex/laches>

This is rampantly false and misleading information.