Why would it be impossible? You're discounting the most probable case, which is that the AI writing is not a substitute for a skilled writer.

Edit: Turns out both Judge Alsup and Judge Chhabria agree that this is not obvious and would need to be defended. Here's Chhabria's statement on the evidence for market dilution:

> As for the potentially winning argument—that Meta has copied their works to create a product that will likely flood the market with similar works, causing market dilution—the plaintiffs barely give this issue lip service, and they present no evidence about how the current or expected outputs from Meta’s models would dilute the market for their own works.

When the plaintiffs don't even attempt to argue the point, that's pretty telling.