Earlier quoted context omitted.
If you steal an unpopular product from a store, the damage is also only to "potential profits", so how does that differ? It's entirely possible no one would have purchased the product and it would have eventually been discarded/destroyed. Or with services, if a barber cuts your hair and then you run away without paying them, do you not consider that theft, even though there's no change in ownership occurring?
The first case is theft as legally and traditionally defined. It has low impact, since the item would have likely ended up in the garbage, but it's still theft as we understand it and as law defines it. The barber example is not theft. You cannot steal a haircut. You may be harming the barber, but it's not theft. Copyright infringement is not theft, because you're not stealing anything. Words matter!
Then why is it legally considered "theft of services", which is a crime that directly includes the word "theft" in the name? https://en.wikipedia.org/wiki/Theft_of_services