> If copyright enforcement was a thing in Shakespeare's time, then a lot more of his plays would be missing today; there would've been far fewer "modified forms" even partially preserving works for which the original was lost, and far less opportunity to produce copies of unmodified forms.

No. His plays were preserved and published by his friends, after his death, so that they weren't lost. Because the curtains had closed, the players had moved on, and the loss of his plays was deemed worse than the loss of monopoly over them. Copyright was originally created to remove the incentives to keep things private and secret; if you have exclusive rights to copy it, and that's protected by law, you're able to release those copies without fear of somebody taking what you've made and pushing you out.

Look at the playwrights who didn't have friends like Shakespeare's. Where are their works, now?

That being said, the world has changed since the 1600s. Copyright (with reasonable term lengths!) was necessary before we had the 'net, but perhaps not so much now.

> Either Copilot ignoring the licenses of source material is deemed legal (at which point people are free to launder proprietary code through ML models, destroying copyright law as applied to software)

The law doesn't work logically like that. If Copilot is deemed lawful, there will be justification of that decision that doesn't allow us to launder proprietary code through ML models. Because copyright isn't about author's rights, and hasn't been since… the 60s? Since some time after the Universal Copyright Convention of 1952, anyway; I'm no historian.

> No. His plays were preserved and published by his friends, after his death, so that they weren't lost.

You literally just said that there are plays of his which only survive in modified forms - i.e. ones which his friends were unable to preserve. Those modified forms are the ones that would disappear in this supposed alternate universe wherein Elizabethan England had copyright enforcement - because those modified forms would've been DCMA'd into nonexistence, and thus those plays would've been lost entirely.

> Look at the playwrights who didn't have friends like Shakespeare's. Where are their works, now?

Christopher Marlowe? https://en.wikisource.org/wiki/Author:Christopher_Marlowe

Ben Jonson? https://en.wikisource.org/wiki/Author:Ben_Jonson

Francis Beaumont? https://en.wikisource.org/wiki/Author:Francis_Beaumont

John Fletcher? https://en.wikisource.org/wiki/Author:John_Fletcher

Thomas Middleton? https://en.wikisource.org/wiki/Author:Thomas_Middleton

John Lyly? https://en.wikisource.org/wiki/Author:John_Lyly

The answer to your question seems to be: they were preserved just fine and dandy.

> If Copilot is deemed lawful, there will be justification of that decision that doesn't allow us to launder proprietary code through ML models.

A license is a license. If it's okay to ignore the terms of the GPL, then it's okay to ignore the terms of any other software license, including Microsoft's EULAs. The law works on precedents, and Copilot's legality sets a precedent that threatens the very concept of software copyright.

Even if Microsoft somehow avoids being immediately eaten alive for lunch by the myriad competitors who'd love nothing more than for Windows to lose its copyright protections (they do have plenty of money to spend on lawyers, after all), their best case scenario of "we somehow managed to carve out an exception for our EULA being enforceable that somehow doesn't apply to other software licenses" would demonstrate rather plainly the fundamental inconsistency in intellectual property law, making it all the easier to justify abolishing it entirely.

Thank you for the solid arguments.