I see you're familiar with Stephen Elop. Also, remember that the people who hired Elop probably hired him with the intention of making a fortune off of that destruction.
It's not that he's some secret agent or some mentally ill person who wants to destroy the company while twirling his mustache, it's that he's a person carefully chosen by people who have made large fortunes from Firefox through indirect means. He would be chosen to destroy it in a way optimized for their gain, like Elop was chosen by the board to turn Nokia into a cheap, obvious Microsoft buy, Clegg was chosen to enable the Tory government, or Sturgeon to make sure that indyref2 never happened.
Google is under no antitrust threat at all anymore. Obama judges don't believe in antitrust. Google wants to get out of paying that 500M/yr, and shitting up Firefox is a great way to do it. They'd be more than happy to throw a couple dozen of those Ms to Enzor-DeMeo or whoever will help them get that done.
How much you willing to bet that he becomes Mozilla's highest paid CEO in history, ruins the product completely, then leaves and ends up an exec at Google or some 80% owned by Google offshoot founded by a Google alum?