Originally I think it was closer to 20 years. Frankly I think 25 years is plenty. A quarter century is enough time to reward the creator of an IP and it respects the fact that all IP is built on top of the public domain so it’s return is a natural part of the cycle.
In any case it’s not like after it expires you could not trade on being the original. It’s not like others could then come along and claim to have been the original creator. And if you kept making works those would each get their own period of copyright.
Originally I think it was closer to 20 years. Frankly I think 25 years is plenty. A quarter century is enough time to reward the creator of an IP and it respects the fact that all IP is built on top of the public domain so it’s return is a natural part of the cycle.
In any case it’s not like after it expires you could not trade on being the original. It’s not like others could then come along and claim to have been the original creator. And if you kept making works those would each get their own period of copyright.