Is Ubuntu replacing everything above the Kernel one piece at a time?
Now I read this. Not very happy.
They're betting they can provide a better UX with their own tool. If they fail, or can't maintain it, or whatever, then that's on them, and people will shift onto other distros.
I'm looking forward to seeing what they do better, in the hopes that other projects can benefit as well.
My comment was specifically in regards to the idea of 'what's wrong with Canonical reinventing everything', e.g., discarding Wayland for Mir. Sorry if that was unclear.
In practice: Yes, Cannonicals questionable open source policy could throw free software desktops a few years back. Just look at Mir for an example. EDIT: or hdevalences comment below!