Please tell me that was sarcasm, friend.
How could someone NOT be motivated in terms of contributing to one of the most epic and enthralling stories in PC gaming history?!? :O
As it’s described it seems more like an art co-op than a video game company. In most video game studios, you have a strictly hierarchic structure, in which orders flow downhill, and in which the developers and designers who actually make the games are usually just ‘following orders’ from above, and have little input on the creative process. If you belonged to a painters studio, however, you would each work on your own things, sometimes teaming up, sometimes not, and going to leadership of the studio only for occasional advice and approval of projects to take on the studio’s banner.
Valve works much more like that painting co-op than it does a typical game studio.
For example, according to Newell, the reason there was no Source engine on Playstation 3 before now was that no one at the company had been interested in building one. Sure, it would have been profitable, it would have been good for the company, but Newell would never tell his employees what to work on. If no one ever decides to make a PS3 engine, then Valve won’t be releasing one. It seems like it couldn’t possibly be that simple, but unless it’s an elaborate ruse, this is how Valve works.
Portal 2 was created by a small team which chose to make Portal 2, starting with the ARG stuff a year or so ago, and picking up steam (pun intended) as others at Valve saw what they were doing and joined the project.
This means that we finally have a hint as to why there has been no new content in the Half-life franchise: No one at Valve is excited enough by the project to work on it.