[BoldlyDubious]

Originally Posted by elcreative

And then we end up with even more laws, even more government interference in areas previously outside government interference...

Actually, more laws are not necessarily an evil. It is only if the laws are bad. Otherwise, removing laws (even at random!) would always be a good idea :-)

Originally Posted by MikeB1972

But then you need an always on internet connection for your media consumption device and an unbreakable DRM [...]

No to the former, yes to the latter. However, media companies are already depending on (not-really-unbreakable) DRM to protect their intellectual property, so nothing would change here.

Originally Posted by Elfwreck

There are very few books I couldn't finish in 24 hours, especially if I planned ahead to have extra reading time.

Yes, of course this kind of system could be defeated by someone dedicated enough to plan in advance, and then execute, a reading marathon. But I would not classify this kind of thing as "leisure reading" ;-)

Originally Posted by Elfwreck

Even ignoring the "must have functional DRM to work" part of this (what prevents someone from downloading an ebook, stripping the DRM, and keeping a copy while returning the "official" version?),...

What prevents someone from downloading an ebook, stripping the DRM, and giving a copy of it to his/her friends (or half the Internet) now? So, nothing new here.

Originally Posted by Elfwreck

... it penalizes everyone who doesn't immediately inspect all their purchases.

The system we are using now penalizes all purchasers, always. My scheme would be an improvement.
Anyway, this kind of precise critique (and maybe some alternative proposals!) is exactly what I was hoping for. I think that media distribution is a field in dire need of innovative business models. And I am beginning to think that to get any real innovation from the existing companies, the only solution is probably using the law to push them. (Which of course opens the way to another set of problems.)

Originally Posted by Elfwreck

No more buying multiple books at once; customers will make each purchase separately in order to give themselves review time, and they won't buy during their lunch hour during a busy week, instead waiting until the weekend or a long enough break to have time to consider whether it's worth keeping.

All true. Maybe we could expand the duration of the "exchange window" as the number of concurring purchases increases? Then again, nowadays we usually get no such window, so even a short one would be an improvement.

Originally Posted by Elfwreck

What's the time limit on a song purchase, an hour?

This is, in my view, the main problem with my proposal. It suits some types of content (e.g., books) more than others (e.g., songs). One (partial) solution would be to exempt media which are considered "too short" (to consume), so that any reasonable duration for the exchange window would be too long. For instance, single songs. Albums, on the other hand, could reasonably be thought to allow an exchange window.
Actually, I tried to find a solution with the (not very elegant, in my view) idea of allowing media providers to exclude each item from the exchange mechanism, provided that they do not use this on a percentage of their output which exceeds a given threshold.

Maybe the key to the issue could be that you get an inferior quality version of the content unless you either confirm the purchase or the exchange window expires, and only then you get the full quality version to keep.
Say, (shabbily formatted) pdf instead of epub for books; low-bitrate MP3 instead of flac for music; low-resolution video instead of full HD for video. Something like that.
(Note: below I will propose a different solution to this issue.)

Originally Posted by Elfwreck

Also: what mechanism do you have in mind to prevent double purchases? If I buy New Mega Blockbuster Novel, the literary masterpiece that's 1038 pages in print and 350,000 words of epub, what stops me from reading 75,000 words in my 24-hour window, returning it... and buying it again next week, and picking up from where I left off?

Easy if the seller is just one, but you correctly point out that (hopefully!) there will always be more.
This is another issue that requires work. Maybe (I'm making this up on the fly, it really needs more thought) the "preview copy" could actually be not a downloaded file, but an online "page" that you get an access to when you make your purchase, and that is common to all sellers of that specific work. It would be easy (and would not entail privacy risks) to forbid multiple accesses to the same "page" from the same IP address, if not sufficiently spaced over time.
I have to think more about this one. Fortunately the solution is not required to make cheating impossible; it only needs to make it sufficiently awkward that 98% of people prefer to buy instead. Ideas are welcome!

Originally Posted by Elfwreck

What prevents someone from not keeping a copy of their favorite book, but just buying, rereading, and returning it whenever they want?

I like to reread my favourite books every few years. But I would NOT like to be forced to cram all the (re)reading within 24 hours! After all, we're talking about spending a few euros/dollars for a book, not hundreds of them. I suppose there's a limit to what people are prepared to put up with to avoid spending such a low sum!