Why Linux is not adopted on a large scale. Because Linux is too fragmented and because Linux users are evil and don't accept the new. Most want Linux to look like the first version of Linux - the command line (TTY).
Or they see that and horses, just forward and don't accept any other Linux distribution than the one they use.
@visone It's not that there should be one system, one DE. But a bit of standardization doesn't hurt while there can still be Ubuntu, Fedora, Arch, GNOME, KDE, etc.
Maybe I didn't express myself properly in the first post. This is not about creating a Linux in Windows or macOS style.
For example, there is Debian which has been around for a very long time. Ubuntu was created to make money like SUSE and Red Hat do. From Ubuntu came Linux Mint which is community based like Debian. Why didn't Linux Mint join with Debian to make it better?
Why didn't MX Linux, Linux Lite, ZorinOS join with Linux Mint to make something better - all of them are based on Ubuntu.
That's what too much fragmentation that doesn't make sense is about.