Both Sonic games are available for purchase for me on Xbox.com.
https://marketplace.xbox.com/en-US/...acd000-77fe-1000-9115-d80258410864?cid=search
https://marketplace.xbox.com/en-US/...acd000-77fe-1000-9115-d80258410863?cid=search
I can only assume that the Golden Axe standalone and packaged game are the same thing and that the package being up for sale is why Sega authorised the BC and why Microsoft worked on it. That the original release was allowed to be made BC isn't really the same thing as the Outrun case. If Outrun were available for purchase in some form, I'd expect that BC would be more likely.
That's without getting into the whole issue of the Ferrari rights having expired. Because publishers have to give permission for their titles to work on Xbox One, I assume that there's specific terms and conditions regarding the platforms that titles are released on - I imagine that Ferrari licensed based on Outrun releasing on specific platforms and would have to grant permission/be paid again for the game to release on Xbox One.
I don't think Outrun's coming to BC. It'd be nice if it did though.