The difference between stealing a ferrari and making an illegal copy of some software is that when you steal a ferrari the person who had this ferrari doesn't have it anymore. But when you make a copy of the software, both you and the person who had the software will have the software - so the person from whom you got the software loses practically nothing.
You're correct in stating that stealing can be thought of as one person losing something, such as a Ferrari, when another person takes it. But can't stealing also be thought of as one person gaining something, without compensating the person he took it from, regardless of whether anything tangible has been lost or not? Does it matter if the developer loses "nothing?" (At least initially?) In effect, doesn't the developer actually eventually lose the ability to one day buy that Ferrari, since he wasn't compensated by the people who took his software without paying? So basically, isn't the Ferrari, in the end, 'stolen' by the very people who steal the developer's software... at least in an indirect sort of manner?