I'm guessing your 60% figure is (a) accurate, and (b) from memory. If so, this is trending in the wrong direction for Microsoft:

http://www.statisticbrain.com/netflix-statistics/

The figure quoted is 50%. Also bear in mind that it's not exclusive, and it's counting all supported game consoles (e.g. including the Nintendo Wii).

My guess is that TVs with built-in Netflix streaming support and AppleTV (now outselling XBox http://macdailynews.com/2012/07/25/some-hobby-apple-tv-outso...) are hurting this.

Given that XBox has been marginally successful as a business and was greatly dependent, for its success, on the dominance of the PC gaming platform, I don't think XBox is Microsoft's ace in the hole.