I don't have a full plan, but I know exactly where I'd start:
A scheme where you lend each copy you own to one person at a time and don't use it yourself, with them deleting the loaned copy at the end, and with a reasonably large granularity like "1 day", needs to be legal. And probably disallow publishers from blocking such a scheme.
Without draconian DRM to enforce, this is only going to work in a fantasy. I mean, piracy already exists today, and this could be achieved if people voluntarily follow these rules outlined.
A scheme where you lend each copy you own to one person at a time and don't use it yourself, with them deleting the loaned copy at the end, and with a reasonably large granularity like "1 day", needs to be legal. And probably disallow publishers from blocking such a scheme.