Funny how different people's experiences can be. When Chrome came out in 2008 I remember trying it just for fun (more than once), and it never clicked with me, so I stayed with Firefox.
What was harder for me was keeping with all the unnecessary redesigns, empty eye candy, dumbing down, the Fennec debacle (exensions used to work, then they suddenly stopped for a bunch of years; plus, no keyword search for no reason).
By that time staying away from Google had become a goal in itself, but I understand who migrated to chrome.
Anyway, I am firmly convinced Chrome won because of Google's abuse of its web search monopoly. The innovations that its team introduced were groundbreaking from a technical point of view, but Firefox was a perfectly capable browser.
I strongly believe it was sufficient. Which does not mean that Chrome was not better when it came out. But most people really don't want to try new tech: because you were excited by Chrome back then does not mean, by far, that everyone on the planet was.
Or precisely because it was not enough to have the better product? Don't tell me you believe that the better product usually wins. Marketing wins.
Microsoft did it to themselves, IE4 was a great browser for its time. It was bundled in Windows, for free, it was anticompetitive, but its technical merits made a big part of its adoption. But as it became old, and Microsoft did nothing to improve the situation. When Firefox came out, it didn't need advertising from a tech giant. It was a godsend for developers (it followed standards!), who advertised for it on their webpages, user tried it and loved the cool new features (tabs!) and installed it on their friends computers, the whole tech world except for Microsoft rooted for Firefox because it was just so much better.
When trade commissions arrived, the job was already done, Firefox had enough critical mass that it couldn't be ignored and IE-only sites were becoming a thing of the past (except for corporate intranets, these have always been the worst). If anything, they helped Chrome more than they helped Firefox as it was just launching during that time.
Marketing alone doesn't win for browsers. It is really easy to switch browsers, all it takes is to have some semi-geek friend to come by and say "hey, try this new browser, it is just like the old one, but better", and if it really is better, that's it. That's how Firefox was winning in 2010. And look how hard Microsoft is trying with Edge, and fail, that's because Edge has nothing over Chrome, unfortunately, Firefox don't have much over Chrome either (yeah, privacy, maybe 5% care).
This was the time of normies. All the @aol addresses still in use were minted here.
Which says that people were trying to learn how to use their computer, right? Nowadays professors need to teach their university students what a file is... I can definitely accept that the users were more technically-inclined in 2004 than in 2014.