So let's assume there are 2 console companies: Company A and company B.
Let's say that company A creates the gamesystem X and company B creates the playingmachine 5.
Both companies have proprietary software on their machines, and both companies have games exclusive to their own machines.
Let's say a third party, let's call it hackerman, makes a hack for the gamesystem X that allows him to natively run playmachine 5 games on the gamesystem X without actually circumventing the DRM software on the playmachine 5 games.
For the sake of the argument, let's assume this is a hardware hack (for example connecting a new piece of hardware that hackerman created himself) and not a manipulation of the software on gamesystem X.
Also let's assume that it is literally impossible to patch out this flaw either as a firmware update on the gamesystem X or as security patches on playingmachine 5 games, such that it would take a whole redesign of the hardware architecture by company A to remove the flaw on the gamesystem X.
Now the question is: would company A be liable for this?
Because the repercussions would be that if people knew that there's an underground hack they can do to run both system games on just one system, company B would lose out on sales of playingmachine 5.
In this case, it COULD also be that company A intentionally made it that way to be able to be hardware hacked in that way, but let's assume that there's definitely no way to prove that accusation.
Also let's assume that hackerman is unidentifiable, the hardware hack is easy and cheap to do (such that even non technical people can easily pull it off) and information and guides on how to do it are either spread through the dark web (so untraceable) and word of mouth.