Linux PC gaming is most certainly in it's infancy, due mainly to the difficulty in getting 3D acceleration to work easily.
If anything, I believe that the XBox would do more to take away from normal PC gaming than the Indrema would do towards the Linux market.
The reason for this is that, given a choice, most developers are going to give preference to the consoles, because the development time of only having to deal with one configuration of hardware and software that a console locks you into makes their job infinitely easier than trying to please the numerous configurations of operating systems, hardware and software that the MS Windows market contains.
The situation will be similiar for the Indrema, and given that the 3D Hardware will be preconfigured, it's even more attractive. The difference, however, is the open source nature of the software. If a great game comes out for the XBox only, there's no way for PC owners to play it (despite the XBox using PC parts) unless it's ported by the game company itself. With an open-source game, however, it's guarenteed that the software engine will be recompiled over to nearly every Linux distro available as soon as it's released and some code monkey somewhere gets access to it.
In alot of ways, the Indrema is competing in a different kind of console market than the XBox and PS2, with the open source nature of the system breaking most of the old rules. It's success will depend very much on the software produced under its new rules.