Patents are for roughly 20 years but copywrite lasts as long as the mouse wants it to...
The Constitution expressly authorizes Congress to provide for copywrite protection “for a limited time”. Currently Congress under “Bono’s law”, extends copywrite protection for the life of the author plus 50 years, or 75 years in the case of corporate authorship. This was passed in 1998 after furious lobbying by the movie and music industry, and is one of the reasons the entertainment industries so loves Clinton and the democrats.