I don't know what environment you live in, but despite the at least 2/3rd adoption rate of Chrome (note, not Chromium but really Google Chrome) over Firefox there is no hate here at all. It's a choice depending on personal preference, and in my case also for FOSS. It's not like Firefox has already lost, which is how you put it.
In fact I've used Chrome for months when I disagreed with Firefox 4's design. In the end I couldn't stand the way Chrome worked and reverted. Besides FOSS, it really is a preference.
I might agree on the topic of making add-ons, though the last time I looked into that (and quickly gave up) for any browser I was maybe 16, which is now 5 years ago. Userscripts is the way I and everyone I know takes, and there Firefox is better than Chrome as far as I know (Chrome requires some tricks because it only accepts scripts from the store these days).