Valve and Vivendi Part Ways
IGN has news that the long running suit between Valve and Vivendi has finally been resolved. There has been some sort of settlement reached, the immediate result being that as of August 31st Vivendi will no longer be distributing Valve titles. From the article: "Valve has not announced a new publishing partner, or whether the company will now solely rely on Steam for distribution. A new publishing agreement would almost certainly be needed for the Xbox version of Half-Life 2 scheduled for release later this summer."
Because it is for X-Box, not PC. In order to release a title for a console system, complicated contracts and agreements must be made between the console maker and the publisher. You can't just press DVDs for X-Box and sell them. Not only would they not work, they would be illegal to sell. Valve would likely have a difficult time getting microsoft to allow them to self publish the game for X-Box.
This doesn't even consider the shelf space purchasing and advertising that is likely needed for a big budget release as this.
These are the sort of considerations that are killing the garage game industry; except for PC games, it is now almost impossible to distribute games without a publisher.