It doesn't. But "you need to get paid" != "I need to pay you for the copy of your work". It's only a possible implication. One that we accept in physical world, but that doesn't work well for digital one - hence my point about finding some other way in which you get your money for writing, without me having to explicitly pay for a copy of your e-book.
The thing is, that in order to enforce the requirement that people should pay per copy, we're lobotomizing the medium. In meatspace, making a duplicate of an object requires work and resources. In digital space, a copy is essentially free (electricity expenditure aside). It's a feature, not a bug. And to restrict it, you need to put in place a lot of legislation and user-hostile technologies that track everyone and make one's life miserable - not to mention destroying the concept of ownership as a collateral damage.
Yes, we can keep the pay-for-copy, copyright-everything model. We can try to enforce the rules of physical world in the digital one. But is it worth the damage it's doing to computing? I believe it isn't, and that's why I think we need to find other ways to pay the creators for the work they do.
The physical book feels like it's worth something. The digital copy doesn't. People have a moral intuition that they should pay you in the first place, and that they should not in the second, and legality is largely just the formalisation of our moral intuitions.
If this were the whole picture, it would be legal for anyone to take the text of Harry Potter and print their own copies of it. Or all books with the same physical "feel" would cost the same.
In the US, its constitution motivates copyright and patent law pretty clearly "[t]o promote the progress of science and useful arts." At least in that sense the laws are to ensure that people have some incentive to actually create new stuff and ideas. Furthermore, people inherently attribute value to the information within or else you would not see price differences in content with the same physical feel.
We largely don't see such differences though. We would assume Harry Potter is what, 3x as good as competing knock-offs? But it's always been priced comparably to other books in the same form factor, certainly not 3x as much.
This does not change the fact that your cat needs to eat.
Perhaps there's another way for you to get food for your cat, than taxing my friend for reading your book?
Assume that the funds required were taken as a tax (a cultural development tax, say), or, if the over-patron were a corporation, from the subscriptions of all users.
The allocation of funds for the exercise, being too easy to open for corruption, would instead be made democratic. That is to say, if you use or enjoy a work, you would indicate as such in a central repository, and some allocation of your input into the central fund would be routed to the creators. This is in effect similar to how Patreon works today.
On the creator's side, the benefits to this are a much more likely source of income; since the fund is state- or corporation-backed, they are much more likely to receive an amount of money if they produce enjoyable works. To raise initial funds to shoot a movie, we can imagine a Kick-starter like system, or the current model of loans and pitches to large individual investors. One definite benefit is that if people have already "spent" the money in this fund, they are much more likely to actually indicate their preferences and allocate money to artists or tool-makers that they benefit from.
There is, of course, the possibility that creators will resort to the normal populism and cookie-cutter approach to content creation that already chokes YouTube and the AAA media industry, but to be honest I don't think that's a problem that can be solved if people continue to pay attention to what they will. Given that that freedom is more important (IMO) than the integrity of art, it shall be so.
The obvious question, of course, becomes "What does the state, and ultimately the people who foot this bill, gain out of this arrangement?" Several things (the profit motive for a corporation doing this is obvious; I will cease discussing them any further); - All media entering the public domain as it's created means that software and culture becomes much more open and universal. Everyone has access to the same media and tools, and can iterate on all of them together. - Any state doing this gets a massive advantage in the culture war. In essence, they have subsidized the production and dissemination of their national values and ideals internationally. This has a tendency for positive knock-on effects in other economic areas, as well. - The death (or at least severe decline) of the advertisement industry. This seems a bit harsh, but these companies are frictional to the economy. I cannot stand ads and would love to see that propaganda machine shut down. - Creation of more niche content. For all its faults, Kickstarter has given small-to-medium sized creatives much greater chances in finding success, and especially when appealing to market segments that tend to be ignored by large content producers. This is an extension of that effect.
There are, of course, downsides. The further spread of echo chambers, the mere fact that this is an additional cost to citizens who may not even want it, the centralization of control of media creation to a state-level entity, possible privacy issues, etc. However, I see those as inescapable trends anyway, and it would be nice to get something out of it for once.
The primary issue I see here is the indirectness between creator/publisher and consumer for what their receiving. Similar to cable: one reason people are cord-cutting is that they'd like to pay for what they want, not the whole bundle.
The Kickstarter model addresses this somewhat, but it doesn't account for long-term continued revenues for the creators for ongoing projects. Also, there have been significant defaults on Kickstarter-type projects, and people (including myself) are becoming increasingly wary that they'll see the fruits of what they paid for.
As for the death of the advertisement industry, they do significantly foot contribute to the income for a lot of media projects, things people aren't willing to pay for directly. While people who pay for subscriptions may think that covers a lot of publishing cost for things like newspapers, it in fact covers only a small percentage of their total revenue. Compare with something like The Information: no ad revenue, small staff, relatively low output, over $300 per year for a subscription.
And, yeah, the state-level entity (which you mention more often than a private one) is going to be hugely unpopular, at least in the US. Look at public broadcasting (NPR, PBS). A small fraction of the budget, still relies heavily on supporter drives, and constantly under the knife. Not to mention the fear that anything involved with the state is propaganda.
A really tough sell, in my opinion.