"Obviously, after the announcement and E3, there was some feedback about what people wanted to change," Microsoft Studios boss Phil Spencer explained to OXM. "There was a real discussion about whether we should have an optical disc drive in Xbox One or if we could get away with a purely disc-less console, but when you start looking at bandwidth and game size, it does create issues."
Spencer elaborated to OXM that Microsoft ultimately decided on adding the Blu-ray drive and giving "the people an easy way to install a lot of content. From some of those original thoughts, you saw a lot of us really focusing on the digital ecosystem you see on other devices - thinking of and building around that."
When the Xbox One was first announced, Microsoft envisioned an all-digital, DRM-tuned console, though Microsoft would shortly after change its DRM policies following blowback from the community. Microsoft Senior Director of Product Management Albert Penello has said that folks weren't ready for an all-digital console. "We may have been right. What we were wrong about was that it's just too soon. People just weren't ready to make that leap right away."