They are in a strange position, but I don't think they are going the way of Sega right now. The market is very different now than it was at that time.
We are applying the status quo as the only possible way to run game consoles when that doesn't have to be true. AMD and Nvidia compete just fine on the merits of their hardware alone without exclusive games.
Even Sony is realizing that they can't only publish on their own consoles. What Microsoft is doing now with Playstation they have already been doing for quite some time already with their games launching day one also on PC.
We also can't ignore that the need for the console is changing with things like xcloud (which runs Xbox hardware on blades, so it gives them incentive to continue making xbox hardware that can both ship as a home console and in blades). xCloud you can even use without any extra hardware (other than a controller) right on your TV with Samsung.
Obviously xCloud isn't going to be the solution for everyone. But we can't apply how things previously worked to how Xbox is trying to just have a different business model. And it isn't anything new with the ABK acquisition. It is continuing what they have already been doing.