You have merely stated your opinion as fact, and not provided anything that can back it up. The current proliferation of content producers (for want of a better word) can be just as easily put down to the larger audience granted by the web.
My point was "less money goes into book in general -> we'll have less books".
You're right that there are other factors at play here, which are all intermingled. For example:
* It's easier to produce content now, bringing down costs.
* It's easier to reach a wide audience. Both because of the internet, and because people have more time to spend on content.
* Technological changes may make many new ways of making money, etc, and in general just change things.
...
Still, at the end of the day, an author has to sit down and write for 1000s of hours to make a book, and to do this over and over again to make a good book. If people can't make money from this pursuit, less people will be able to do it. Maybe in a few decades, there'll be other ways to get compensation for these pursuits that has nothing to do with copyright. I still think the mistake is to think only of the Disney's of the world without considering the tiny indie studios, the small-time authors, who barely manage to get by today. They must be a part of this conversation as well.
Authors have managed to produce novels while holding down demanding full time jobs (or in at least one bestsellers case, still in full time education) at the same time. It is not necessarily the case that the only way books get made is full time writing.
You could also argue that the reduction in books from reduced copyright would be balanced by an increase in currently unwriteable "remixes" of existing works. Copyright could be, for example, the only thing holding back an explosion of people making enough to live on publishing fan-fiction. Who speaks for them?
There's still scope for a sweeping reduction, in the States at least. Reducing the duration from "Year of Authors death + 70 years" down to, just "Authors death", for example, clearly couldn't lead to any given author producing fewer books.
I absolutely agree that if there is a forum on the scope and duration of IP, small-money authors should be represented. It doesn't seem like that will be happening any time soon though.
One minor nitpick: "Reducing the duration from "Year of Authors death + 70 years" down to, just "Authors death", for example, clearly couldn't lead to any given author producing fewer books."
You can't know that. Lots of make money specifically to leave to children, and for many others it plays a significant role.
I agree about all the other points - there is a lot of unknown in this field. I'm just not crazy about people saying "let's scrap this at least partially working system, and replace it with something I just made up". I'm especially not crazy if they don't even demonstrate a basic understanding of the issues.
He was slightly more swayed by the moral argument: his children had done no work for this income, so why should they be preferred over the rest of society in benefiting from his creative output?
A tempting response is "So something like min(20years, authors remaining lifespan)" but that could leave early work (often less commercially successful) with an expectation of a longer copyright duration than later work.
A fixed period risks letting copyright lapse in an authors lifetime, which is certainly offputting to anyone who, for example, dislikes fan-fiction. So we move towards "authors remaining lifespan + rough average lifespan" as a compromise.
Seems reasonable, although I find one way to increase my understanding of any issue is exactly this kind of discussion.