Yes, the question is completely one of physicality. Because physicality places a limit, and therefore a finitude, on supply. When you make a copy of something, you don't decrease the supply of the thing that the original vendor has; you've just created one of your own without taking one from the original vendor at all, regardless of whether you'd paid for it (buying) or not (stealing). Correct. But then again effort doesn't always correspond to marketability in the first place. People may just not listen to your music at all if you can't distribute it widely enough to the right people. A lot of the anti-anti-pirates would state the inverse, that's it's in fact irrational to equivocate piracy with physical theft. I think the question is one of physicality. For some reason, something has to be able to be held in your hand or it doesn't count.
It doesn't matter that it's the same group of songs, the same effort put forth to produce it.
Somehow the digital version is okay to steal, in fact we are somehow debating whether it is even theft. It's irrational.