Legally it doesn't matter - in fact you could say the courts practically endorse making emulators to compete with existing platforms, given quotes like this fro

Legally it doesn't matter - in fact you could say the courts practically endorse making emulators to compete with existing platforms, given quotes like this from Sony v. Connectix (where Sony attempted to sue Connectix for making a commercial (sold on shelves) emulator for the PlayStation which was then being actively commercialized): > The Virtual Game Station is a legitimate competitor in the market for platforms on which Sony and Sony-licensed games can be played. See Sega, 977 F.2d at 1522-23. For this reason, some economic loss by Sony as a result of this competition does not compel a finding of no fair use. Sony understandably seeks control over the market for devices that play games Sony produces or licenses. The copyright law, however, does not confer such a monopoly. See id. at 1523-24 ("[A]n attempt to monopolize the market by making it impossible for others to compete runs counter to the statutory purpose of promoting creative expression and cannot constitute a strong equitable basis for resisting the invocation of the fair use doctrine."). - 9th Circuit Court of Appeals, ruling in Sony Computer Entertainment v. Connectix Corp.