I would see no argument with this as well, with the exception that 70 years is a recent extension, and is far longer than it should be.
Importantly, there are such vast quantities of library copyrights and patents, there would be a gigantic amount of content released all at once. So the value of entire genres of material would be tiny, unless they were value-added with superior editing, for example. Like Criterion Collection movies today.
They're always telling us how we didn't do anything on our own, but when they do something they say they did it on their own and they want to get paid for it forever.