I think you've oversimplified the pre-existing Google/Mozilla distrust plan, and your misapprehension about what was happening has harmed your understanding of the economics of this acquisition.
You're right. I probably do need to go back and re-examine the details. Generally when disagreements happen, one or both parties is missing something. At the same time, I still feel this is far too nice an ending for Symantec given the shit they pulled.