Yes, Mozilla needed to invest in Firefox speed, and did so in the FF4 cycle as you're doing so currently in Memory use. Firefox(1) currently works better for my 100+ tab browser habit than Chrome, so despite your older code base and smaller size I think you can produce a competitive browser engine even if you're playing catch up now.
But I think you've way overcompensated for the FF4 development cycle. Face it, you were losing users to Chrome, and you will continue to do so. Chrome is a competitive browser from a well known name, backed by the kind of company that can drop $12B on an acquisition without breaking sweat. I see dozens of Chrome ads every day as I browse on Linux (they're on this page!). You just can't expect that not to affect market share.
In reacting to this you seem to have pushed hard to produce a more Chrome-like experience. No-one objects to investment in speed, memory use, multi-process support etc., but Google is either ahead or capable of catching you in all of these. At the same time you're destroying your USPs. You must occupy a different niche to Chrome or you will lose.
You used to have a huge add-on and customisability advantage, but as already discussed are damaging that (plus putting off the users who depend on add-ons -- if they do stay on FF it'll be harder for them to trust add-ons if they've broken before).
You used to have a browser that competed with IE, not so good for enterprise use, but it was competing and it was cross platform. You're abandoning that for version free upgrades. That's too much external trust and too little control for most enterprises, who don't want the extra risk. Asa says web applications don't show versions, but we only use web applications where we have a business relationship with the supplier, have done our own testing on the site and have clear idea of its support; having such an external dependency is not taken lightly.
You used to have the advantage of being Open Source, and the army of contributors who went with it. But webkit is open source too, and Mozilla is now pretty strict in what it accepts. If you want to add new functionality to web browsers it's certainly not harder to get code into Chromium.
What is Firefox's Unique Selling Point now? The fact that you're tough enough to take a principled stand against H.264? I love you for it, I really do, but I know it's irrelevant to the world at large, even most of the tech world. It won't be close to enough.
Maybe I'm wrong in characterising Mozilla's attitude, but your mission does seem to have become using the power that our browser share gives us to "do good for the internet". Which is not so very far from farting around worrying about the next big idea rather than serving your users best. I'm unconvinced you'll keep them; you're burning community goodwill like there's no tomorrow, and with them goes your influence.
Seriously, what is your market positioning in comparison to Chrome, I really can't see it?
(1) Today's bit of crazy is that version numbers are not webby enough, so I guess there's no point referring to a specific version any more.