Linux is super fragmented (and generally has been historically).
If more people in Linux agreed to develop, use, and support the same distro–similarly to how most of us use the same kernel–then that distro would probably be better than Windows and more people would move to Linux.
What is the issue with systemd?
SystemD is fucking great and i will never go back to anything else, and this argument is the reason OP doesn’t understand why a unified agreement on a distro is fucking impossible.