What about Sony vs. Connectix? That case seems to have established that US copyright law does not confer a monopoly on devices or software to play commercial games.
They was both A) a case decided before the DMCA was law, and B) the DRM system of the PS1 is pretty much solely focused on legitimate PS1s only playing legitimate discs; there's nothing in most games stopping other systems from reading everything off the disc freely in cleartext.
https://en.wikipedia.org/wiki/Sony_Computer_Entertainment,_I....