Originally, US copyrights were 14 years with an optional 14 year renewal and you had to register it with the government and deposit a copy of it in the Library of Congress [0]. Copyrights were also limited to Americans because the purpose of the law was "the encouragement of learning" not allowing corporations to profit off of stuff they made a century ago. Article 1, Section 8, Clause 8 of the US Constitution also says that the purpose of copyright is "To promote the Progress of Science and useful Arts" and specifically requires that copyrights be for a limited time.

In other words, we basically had that and politicians created the current system of copyright out of it thanks to 200 years or so of lobbying from special interests.

[0]: https://en.wikipedia.org/wiki/Copyright_Act_of_1790