This is a great comment in that it shows the cognitive dissonance of slamming Canonical for trying to commit upstream while also slamming them for their past lack of upstream commits, in a handy Twitter length package.
Sorry, but sending code upstream for their distribution-specific display server (which has no technical reasons for existing) isn't benefiting the rest of the community.
Given the size and content of the patches under discussion here, I think they'll be fine maintaining that level of Mir integration with the Intel drivers themselves.
Sure, Intel's actions are more symbolic than anything else.
Ubuntu has received a lot of flack for their aggressively NIH attitude, but being able to point to support for their NIH-motivated products in other widely-used software would signify some amount of acceptance of their actions in the wider community.
I think their are many people who don't want to send that signal.