surely at some point before halo infinite comes halo 5 joins MCC or atleast able to buy it on steam?
There are no plans to bring Halo 5 to MCC, also having it done before December 8th would be impossible as almost all of the team are heads down on Infinite. MCC is handled by a much smaller team that already have a roadmap of features and bug fixes they are working on into next year.
If you wish to further discuss Halo 5 coming to PC, feel free to use this topic:
https://www.halowaypoint.com/en-us/forums/6e35355aecdf4fd0acdaee3cc4156fd4/topics/halo-5-on-pc/525dadaf-2c2b-4626-8c48-c7c83e150d46/posts