Because It will be awesome.
I want to see this collection on steam.
With steamworks, achivements, steamplay, cloudsaving.
With steamworks you can install games many/unlimited times and on many/unlimited pc's as you want.
If 343i don't decide to release this MCC on PC then they should turn around and just port Halo 3 to PC instead and I will be really happy.
I'm a true PC gamer and I love Halo and 343i.
Don't forget, I play Halo Custom Edition on PC making models, animation.
343i you got PC fans that love halo
So you guys vote and let's see where this lead too. Just like what Halofollower said "Never give up hope" and remember 343i said we have to keep asking for it.