As much as I love Firefox, the only thing I can read here is: We have failed to diversify, and we would really like our yearly $400 million to pay our CEO
That, and the unfortunate truth that if Firefox only exists because Google needs a fig leaf against monopoly charges, it hasn't proven its value in enough ways for it to stick around. I love Firefox, but the market in general has centralized on Chromium for a lot of reasons.
Philosophical reasons to exist are great, but philosophy doesn't pay the bills, it seems.
It doesn't take a lot to read between the lines here. It's not like selling off Chrome would somehow invalidate the Open Source Chromium project in any way.