These laws could also set the counter for let's say 5 years after the death of all of the original authors or something like that. There is no reason for these rights to transfer indefinitely.
That's not how patents and copyright work. These are government granted monopolies. The wording goes the other way around: The government is authorized to grant these monopolies. That's very unlike rights to life, property, etc. Patents and copyright don't come from the same tradition as proper human rights. They're different, and there is no human rights argument against limiting them sharply, at least not in the US constitution.
"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness."
The signers knew what they were doing was against the Kings laws - but they said, for the first time, there are higher laws that everyone is entitled to. Copyright and patents, while maybe good law, are not among these.
In a word, yes. The entire purpose of copyright is to enrich the commons by granting a limited term monopoly. Without that purpose in mind, copyright loses legitimacy.
It's a government granted right, and, in the US, there is specific authorization in the constitution to make such a grant. The term could be set to any term, and there would be no underlying constitutional of inherent human rights case against such a change. Unlike actual rights, copyright is whatever governments say it is.