> it needs shortening but any proposal with 'original creator' center and foremost is basically ignoring the reality of modern content production

There's a handful of ways to do it if you are not going to center copyright terms around the life of the original creator, some of which I think are better than others but I'll try to leave most of my opinion out of this.

1. You can center it around first publication. In this scenario you actually do not automatically retain copyrights unless you actually publish, and then you would likely need to define in detail what publication is.

Is sharing in an email message or WhatsApp "publication"? I would argue not, but the law would need to reflect this. Again without spinning this discussion off into a tangent, there's probably multiple ways you could write that into the law, but some language like "made available to the public for free or for a fee" etc. or whatever the American legalese equivalent of that sentence would be. IANAL

2. You could center it around the registration date with the Library of Congress. Again, in this scenario you do not actually automatically retain copyright, and while it massively simplifies the letter of the law, it shifts more of the burden to the Library of Congress to retain records. In this scenario, you would file a registration with a full copy of the work or specifications or some other means of defining it in the case of things like statues. Probably the main advantage of this is that the Library of Congress then has a full copy of the text, source code, blueprints, etc. that it can then automatically publish itself upon the copyright's expiration.

Anything you do though, I would do it for a fixed term, say, just to pick a random number out of the air, 50 years and no more. No renewals, just one copyright term and that is it. You can choose to relinquish it to the public domain before that time has come to pass but you could not extend it.