I don't think they are doomed. There are 5 million shipped consoles with it included. They aren't taking that option away so it's likely to grow even if it's from people who can't find the 399 model.
I know Yusuf Mehdi when being asked if he worries about optional kinect getting less developer support said: "One thing I should say is that we made this decision in conjunction with our games publishers and our entertainment partners."
I hate to say he was lying but Twitter comments from people at studios don't seem that way. I can imagine advertising companies whom may have been sold on every person having and interactive add device are probably a bit disappointed too.
Oh source: http://www.forbes.com/sites/insertcoin/2014/05/13/microsofts-yusuf-mehdi-explains-the-xbox-ones-split-with-kinect-2/