> If a work is entirely digital, what is the difference between the original and the copy?
The difference is that the original instance of the work potentially required considerable time and money, whereas its copies are essentially free to produce. There's no difference between the bits of the "original" and the bits of each copy, but concluding that copies of a work should be free for all because the act of creating that copy is free, is fallacious and intentionally misleading.
What well-researched book have you written for free?
What hit album have you (and your band-mates) written and performed for free?
What feature-length, CGI enhanced movie have you produced, cast, and distributed for free?
What TV show have you produced, cast, and distributed for free?
I'm not trying to call you out specifically, but your post uses "I", so I'm responding appropriately. For better or worse, garage bands, open source developers, and patreon writers are the vast minority of copyright users.
The difference is that the original instance of the work potentially required considerable time and money, whereas its copies are essentially free to produce. There's no difference between the bits of the "original" and the bits of each copy, but concluding that copies of a work should be free for all because the act of creating that copy is free, is fallacious and intentionally misleading.