I've always viewed it as a loss leader. You cant keep giving away games that go for $10-$30 every month without it costing Sony $4 and change. It helps move hardware which in turn moves software/dlc which in turn can create a profit.
Getting an XBOX One for me is like being in a bad relationship but staying together because we have kids. XBone we have 20000+ achievement points, 2+ years of XBL Gold and 20000+ MS points. I think its best we stay together if only for the MS points.
Nintendo Treehouse is what happens when a publisher is confident and proud of its games and doesn't need to show CGI lies for five minutes.