It’s because Chrome is so ubiquitous. You go to any Google site, particularly search, in a browser other than Chrome and you’re presented with notifications to install Chrome. Plus, its integration with Google accounts presents a great value proposition for many users.
Personally, I was on Firefox for years until I got a MacBook Pro in 2014. For whatever reason, Firefox would constantly crash, so I switched to Chrome. I only went back to Firefox in about… 2019(?) when they released Quantum and I’ve been on it since. It’s really the perfect browser, particularly with extension support. I also like how on Android you can install uBlock Origin.
With Google’s impending Manifest V3 looming on the horizon for all Chromium-based browsers, it just further cements my decision to remain on Firefox. I do keep Brave around as backup for the extremely rare situations where something for whatever reason doesn’t work in Firefox, but that’s becoming exceedingly unnecessary.
It’s Kotlin, actually.