Why does Microsoft play ‘me first!’ with cross-platform releases?

If content is obviously superior on Xbox Live, why then does Microsoft feel the need to strong-arm publishers into first-release contracts for their digital releases? There are plenty of justifications for such a policy, and you can be sure that they all center around financial benefits that accrue to Microsoft. But in order to soften the mercenary truth of the matter, Microsoft VP Chris Lewis fell back on some trite and dubious claims about these decisions being in the best interests of consumers.