Google used a lot of its gigantic resources and ad spaces to advertise Chrome everywhere. It's been installed and enabled by default on most mobile devices for years. Google paid software publishers to have Chrome distributed through other software installs (it also bundled it with its own software like Picasa and Google Earth). It also paid my local (state-owned) public transport operator to display gigantic banners in my train station. It organized events in my work community to promote its software and services, including Chrome of course. For years, its search engine told me to install Chrome every time I access google.com from another browser. Google stills serves old and ugly results page when I do search from Firefox (e.g no chart shown when searching from Firefox, although every other financial websites is able to perfectly display their stock charts in non-Chrome browsers). They've even been fined billions(!) of EUR for illegal practices involving the distribution of Chrome)[0].
People may have made different decisions to chose their browser for good reasons, but Google also built a monopoly for very good reasons, too. Users were and are still constantly pushed and incentivized to use Chrome, because of extensive, multi-year PR campaign, digital and outdoor ads, but also technical tricks.
[0] https://ec.europa.eu/commission/presscorner/detail/en/IP_18_...
