Ultimately Microsoft is a financial organisation and they will always pursue the whatever will provide them with the most profit. Given how popular on demand video has become its not at all surprisng that they are pursuing this.

Given the amount of revenue Nintendo have managed to generate from a casual focused system Microsoft must be aware that they would also like to corner that part of the market hence the focus on kinect.

Ultimately sequels sell really well, they have brand recognition on their side and an established fan base. Marketing a new ip must be very difficult given how much a triple A title costs to produce and what the risk/reward scenario must be.

In my opinion we will continue to see a lack of new ip until Microsoft recognise they are losing the core market due to inaction. When will that happen? Who knows