Thief developer Eidos Montreal has laid off 27 of its employees today, with a full statement from its praent company Square Enix, explaining why they were let go:
Yes it is true we've let 27 people go today, unfortunately it's something that every major studio has to do sometimes in order to ensure you have the right set up for current and future projects. It's never a nice thing to do but we are genuinely trying to offer as much support as much as we can. We're trying to re-locate as many people as possible into other roles here or at our other studios and we've been in touch several studios in Montreal to arrange a career day for those affected by this. We're very thankful for all their hard work and we sincerely wish them well.
It's always unfortunate when employees are let go after the release of the game, but it's a fact of triple-A game development. With no foreseeable projects to work on, many employees are let go after the development of a title regardless of how well the game does.
It's worse if the game itself doesn't do as well as its publishers hope, just as Thief received middling reviews across the board. We however loved Thief in our review of the game, which you can read here.