Google has been dodgy for a long time. They've been abusing their dominance to maintain their monopolies and erode our freedoms. No matter how many times developers like that of uBlock tell you that the blocking experience isn't as good in Chromium based browsers compared to Firefox, due to decisions made by Google, people don't listen. Now Google is attempting to insert DRM into webpages to force us to look at their adverts, that's insanity and everyone knows it. But still people support them by using their products. I can understand using YouTube, no other video site comes close in terms of content. Gmail is the class leader for email. But search? You can't even get results on the first page without an adblocker. And their browser, along with the derivatives? Why are people empowering Google's fuckeries? It makes no logical sense. People even attempt to hold Firefox to standards they turn a blind eye to for Chrome. I'm baffled, confused, perplexed by it all. I just don't get it.
I used to switch browsers a lot back in the day (although I primarily used Opera [Presto], after Opera dropped Presto, I mainly use Firefox), and I personally witnessed the impressive growth of Google Chrome.
I have to admit, Chrome is generally faster in various aspects - from startup time to loading pages, it excels. Even in 2008, people were amazed at how snappy Chrome was. The only downside back then was the lack of extension support but I did find some people sticking with it because it was honestly fast.
When the extensions were introduced around 2011, Chrome's userbase skyrocketed from there. Slowly bleeding Firefox's userbase dry also in the process because Firefox may have addons, and during the time of release, Firefox had superior addons too. Main problem is it was slow and clunky.
Now to think about it, despite Chrome's overall speed advantage, there were notable periods where Microsoft had a chance to capture the userbase and impede Google's growth. Notably, Internet Explorer 9 introduced GPU acceleration, which made browser rendering remarkably fast (Chrome and Firefox took a while to catch up on this).
Then there was Edge (EdgeHTML), which proved to be twice as responsive and generally snappier than Chrome.
So why did people not switch to Edge and instead opt for Chrome, even though Edge is faster? Well, it all came down to the user experience. Edge encountered issues right from the start, getting blocked by Google (Oops, this browser is not supported).
Obtaining the latest version of Edge was troublesome, relying on Windows updates, which are notorious for their slowness (sometimes you don't get the update right away, even if you check for updates). If a site issue required a fix available only in the latest update and it is not yet available,tough luck!
Additionally, Google aggressively marketing Chrome whenever it gets the chance. From its website, to bundling it on installers just so it gets installed along with the software you are actually installing.
By the time Firefox released Quantum in November 2017, it was already lagging behind in terms of user count.
So, basically, the tl;dr is that Google devised a brilliant strategy to become the top dog of the web.
Users preferred Chrome because it's fast and consistently less troublesome than other browsers (it certainly helps when the two most popular websites in the world are affiliated with Chrome's parent company).
The updates also are effortless (even a bit aggressive, in my opinion) to the point that users may not even realize Chrome has already updated, which adds a lot with being consistent and there. You cemented as being the best browser for the majority of the people.
There is a shockingly large number of people who go through life in general reacting to things around them and not thinking critically in any meaningful way. Chrome is "normal" to them, it's the default, the status quo. On top of this, our monkey brains tend to rebel when asked to consider making even the slightest change. I'm a bit guilty of this as well. For example, I stayed on reddit for years, even though it wasn't something that was an essential part of my life and was clearly harmful.
The reason people are more critical of Firefox is that it is different, an outlier to them. Maybe they think it's too confusing to switch, or they try but they never get past that initial feeling of discomfort from even the slightest of changes, never give themselves a chance to acclimate, never learn how to make it a far superior browsing experience to Chrome.
Then because it is new and different, such people will start to perceive everything as dangerous and bad. That's why people are still saying Firefox Mobile is slow and buggy as an excuse to stay on Chrome, in spite of the fact that all metrics say otherwise.
(Note: This doesn't include iOS and Mac users, for whom Firefox is basically a worse Safari, but that's thanks to Apple, not Mozilla.)