Do you understand the meaning of zero-sum? The russians are cutting work on Obsidians part but hiring people on their end so we can infer that they still need roguhly the same amount of workforce working on the game. The russians are simply cutting Obsidian off and hiring their cheaper workforce after Obsidian did all the heavy lifting. How's that good for Obz? I'm sure they wanted to milk the MMO for as long as possible as having a steady flow of income is great, but Mail.ru is probably going to cut them off completely at some point.
That part isn't good for Obsidian, but if they made enough money beforehand before it that happened the deal as a whole might have been. No business arrangement is perpetual.
Maybe Obsidian wanted to have something in the pipe to fill the gap when it ended and didn't find anything. Maybe that was even because the Russians ended the deal earlier than anticipated. That could be bad for Obsidian, but if the deal had made enough money before that it still could have been worth it.
Obviously we don't know if any of this is true. The point is just that there are multiple scenarios where the deal could have been good for Obsidian overall
and layoffs happened.
