Something to consider is that Bungie/Activision may have made the exclusive offer to Sony first (and possibly to Sony only). You're correct that Microsoft put Bungie on the map, but you're forgetting that Bungie was often not particularly happy with the relationship and broke it off as soon as they were feasibly able too. You also might remember that before Microsoft Bungie was an up and coming studio in it's own right with a few critically acclaimed games under it's belt. Halo likely would have been a hit even without Microsoft, although possibly not as big of a hit (and it's arguable that the XBOX would have been a complete failure without Halo). Bungie would have very likely continued to be a successful company even without Microsoft's support, although it's hard to say if a multiplatform or Sony exclusive Halo would have been as popular. Halo's reputation (accurate or not) as the only XBOX game worth playing* certainly helped focus a huge amount of attention on it. The game might not have gained as much attention in the much richer Playstation and PC libraries. Anyway, characterizing Microsoft's treatment of Bungie as nurturing and caring is pretty inaccurate, at least according to many reports. It's also worth pointing out that Bungie reportedly had a good relationship with Sony prior to being bought by Microsoft. * Despite popular opinion, teh XBOX did have a handful of really great games besides Halo. I'm very fond of Panzer Dragoon Orta and Jet Set Radio Future (both of which were wildly unpopular and sold poorly).