Earlier quoted context omitted.
> The reason Windows doesn't have fragmentation is because it's a closed-source operating system with internet enabled functionality that is centrally controlled by Microsoft with an iron fist. Sure, being closed-source prevents fragmentation from the start coz there's nothing to fork from, but it's not a requisite. There are many open source projects with less degree of fragmentation with major marketshare winners t…
Open source web browsers aren't fragmented? Really? There's dozens of forks of Chromium. They're so prolific that everyone is advocating a different one. Opera is better, no wait brave is better, no actually arc is the best. But no wait, edge is pretty good.
However you like/dislike any of the popular choices, the point is that other players in the ecosystem can mostly target the top choices and be reasonably sure that they cover the vast majority of user bases, so that upper layers could flourish. Except for Edge being the default on Windows, sane companies wouldn't care about minor players like Opera/Brave/Arc.
(You could also argue the degree of open source in these cases but that would be a different issue.)