This is the correct answer. The problem is that copyright law was created in a higher friction environment and it cannot adapt to the present.

If I bought a book, made a xerox of the whole thing, and then sold the book to another party, I have committed a copyright violation that is in theory actionable. This is basically unenforceable; in theory if it came to light that I had a copy of it and had sold my copy then there is an actionable claim, but nobody is going to do this. But the friction here is high so we know that we can live with this, because nobody could possibly do this at a scale that would make a difference.

With pure digital goods the friction drops to zero. For a while friction kept up with technology; when CDs were first around, making a digital copy of a CD was just not feasible. You maybe had a 1GiB hard drive and could store a single CD on it. With mp3 compression becoming mainstream that math changed, but at least games and things like that, that were not easily compressed, were somewhat safe. CD-R allowed you to break this but was high friction. Same with DVDs when they were first around.

But now storage is no longer a concern, so all of that friction has disappeared.

Streaming and on-demand content gives a possible solution to this, and that's why everything is moving in that direction -- trying to increase the friction of creating durable copies of the media. As soon as you allow backup of the content (as in the GP's post) then everything breaks, so that's the thing that you (as a content creator or distributor) have to fight.