It's not just about the browser by itself.
Don't forget all the great extensions built on top of Firefox.
Until Chrome has attracted developers to build great extensions on it, Firefox is going to stay as my main browser.
Yes, firefox is a platform. The total value is higher than the thing itself, and that makes it hard to displace. Like DOS and Windows. Adblock is very popular, and although I use Greasemonkey (and scripts accumulated for that platform) and others, I doubt that many of the userbase do. And so for them, this isn't a factor.
It's worth remembering that Google doesn't care to win this war - they just want faster browsers to drive web and webapp usage.
Do GM scripts from Firefox work without modification?
Thinking further, most GM scripts only operate on the html received, and are independent of the browser. So all one needs is the GreaseMonkey platform to act as a holder, and existing GM scripts can run straight off, without modification. (maybe some use special Firefox functions, or their job is to interact with firefox specifics, but I think most wouldn't).
But doesn't that give Google an even better chance of succeeding? Unlike Firefox, they're not blinded by competition - all they want is a superfast browser. And that's what most users want.
As for Adblock and Greasemonkey, neither plugin is particularly complex. Once plugins for Chrome get big, I'd give it 3 weeks before we see a working version of each.
I'm confused by your first paragraph, because you seem to be agreeing with me semantically, but disagreeing syntactically. I think if you expand a little it will become clear to me. :-) BTW: Most users want features more than speed (otherwise it doesn't do what you want, but fast).
In your second paragraph, I think you're underestimating the power of a platform (which enables MS to make so much money BTW). It's an incredibly powerful competitive advantage. Remember monkeyboy: "developers, developers, developers".
I agree Adblock and Greasemonkey can be duplicated in negligible time (it took 7 iterations to get the latter's security model right, but that work is now already done) - but that's only 2 addons. How many man-hours to duplicate a comparable eco-system of addons? Secondly, Greasemonkey is itself a platform - how many man-hours to duplicate all the add-ons for that?
It's not enough that there's the ability to create the addons - they also have to be created, and that takes time, during which more addons are created and refined for Firefox... I'm not saying it's impossible to catch up, just that it an established platform is a powerful factor. BTW: Chrome isn't even released for Linux yet. It's fast, yes, but...
An exception is if Google can make Chrome plug-compatible with Firefox plugs-ins; and if a Chrome Greasemonkey can be made that is plug-compatible with Firefox Greasemonkey. From my fiddling around with these technologies, they both seem to be to be horrendously tied to Firefox specifics. They don't need to be, but they are. IMO, anyway. :-) NB: even firefox 2 and 3 aren't plug-compatible! :D
However, perhaps none of this matters, because (I think) few people use many add-ons beyond adblock. But I really don't know. Maybe they do? I guess Firefox's extensions page has stats, so it would be easily estimated. Oh well, why not some data? It's so much more fun to argue with facts to throw:
Adblock: 627,380 downloads weekly. That's well over 25 million pa. mmmm... the currently most popular plug-in is actually "Video DownloadHelper", at 701,065 weekly downloads. Here's the 20 most popular add-ons:
https://addons.mozilla.org/en-US/firefox/search?q=&cat=a...
