In fairness to Firefox, at this point I'm just waiting for their dev tools to get as good as Chrome's before I seriously consider switching, and other efforts like Quantum certainly make the prospect even more attractive. Once they have me on desktop, I'll want to switch on mobile as well for the state syncing benefits.
I wouldn't be surprised if a sizeable portion of Chrome users were in a similar boat, quietly waiting for some small aspect of Firefox to improve.
2 things keep me on Chrome. First, the overly large titlebar on Linux. I've tried some addons to make it more like Chrome but they all look like shit. And second, the dev tools. I find dev tools in Firefox clumsy to use. I believe I originally switched to Chrome for the dev tools when I ventured into frontend development.
Just installed Chromium to compare. When maximized, the Chromium title bar is 65px high on my system, whereas Firefox's takes 70px. I should note, though, that I have set my window manager to hide the default window decoration on maximized windows, which helps.
I even develop stuff on Chrome where I'm planning for the final deployment to be to embedded web views on other platforms (e.g. embedded WebKit on Apple platforms). The dev tools are just that much better. Fixing the occasional incompatibility is more than outweighed by the superiority of the Chrome developer console.
All the older administrative workers at my office, who have used IE for years (often because their enterprise apps required it) are pretty grumpy about Edge.
I think it's mainly just because it's different. A lot of people don't like gratuitous change (something most tech companies don't understand at all). I'm sort of in that camp myself. I basically abandoned Office when they came out with the Ribbon UI, and I still haven't liked any new Windows compared to the "classic" NT desktop.
I wouldn't be surprised if a sizeable portion of Chrome users were in a similar boat, quietly waiting for some small aspect of Firefox to improve.