I'M not a big video game player but there are a few old PC games(half life original) I would love to have ported to Linux. Window$ also occasionally has a software package or two that Linux could really use. How hard would it be to port some of these old games to Linux? I'M sure it would be a job but nothing compared to actually writing and designing these games to start with. I was wondering why has there been no companies or even Linux enthusiast groups offering this. I thought for the relatively small job that would be compared to actually building the game, some company might invest in such a product conversion for profit. I would have also expected Linux groups to take on such projects for the fun of it. I know they would have to abide by the companies permissions and all that jazz, but I would still expect to see it going on.
I've not looked into all of the specifics, but I'm sure that one of the major obstacles are the original developers.
To port a piece of software, one would have to de-compile it, giving full access to the original source.
If "Company X" were to allow that, then "Company Y" would be able to examine and implement that code into their own product. So that's a game engine, patches, graphical design elements... All exposed and available to a competitor.
I'm thinking that this is at least one reason for the lack of porting.
Then there is the viewpoint that Linux just isn't a viable target audience for game developers.