I think you're confusing defaults with lock-in. Safari, Edge, and Chrome are native browsers tightly coupled to their operating systems. They can't be removed.
Further, anytime a user has to connect to an account for email, calendars, and other essentials, the OS will direct them through the native browser app. This means the so-called "popularity" reflects little more than the number of active devices: Android > iOS > Windows.
Not all browser marketshare statistics are sourced the same way, but often those native redirects aren't included, likewise for things like electron and CEF use.
Also Edge use being far lower in Desktop use indicates that there's little difference between defaults and lock ins functionally.
Further, anytime a user has to connect to an account for email, calendars, and other essentials, the OS will direct them through the native browser app. This means the so-called "popularity" reflects little more than the number of active devices: Android > iOS > Windows.