I don't see what is really wrong with 360 sales... Sony was only 60,000 consoles ahead worldwide. At that rate it will take over two years to catch up. And that is after Sony slashed price, had a massive marketing blitz (It was almost impossible not to see a PS3 commercial before and during Christmas), won/are about to win the HD war, and introduced another product that was yet another $100 cheaper... So, really they had a $200 price drop because most sales are probably 40 Gb versions.
Microsoft hasn't really done much since Halo 3 release. They had a $50 price drop last August and hyped Halo 3 through the roof but after September they have been very quiet.
Now, 2008 is here. And Microsoft has yet to speak about their game offerings, price drops, or anything else yet. Not because they don't have them. Fable 2, Too Human, Halo Wars, Alan Wake, and some Rare title(s) are all but guaranteed for this year. Microsoft hasn't even really showed anyone these games yet, so it is relatively unknown what kind of features they have whereas KZ2 and MGS4 have been shown a lot and everyone knows what they will offer in detail. Also, it is well known that Microsoft has brought down the cost of 360 manufacturing drastically and will get more when they reduce the size of the video processor in summer.
So, what's the big problem? They have lots of room to cut price and they have new and existing IP coming out that should appeal to potential consumers. Really, the biggest problem is in getting over their hardware reliability issues. If you look at worldwide sales, 360 is starting this year off better then last. Last year to start January they only had 144,033 consoles sold WW in the first week. This year they had 206,098... What is wrong with an over 30% increase? The year is still young and to write any of the console companies off is really uninformed.