As we've seen with Watch Dogs, third party games don't seem to affect XB1 positively. People buy the XB1 for exclusives and because they are loyal fans of the brand. The mass market has basically rejected the product though. The $399 SKU seems to have actually done nothing more than to give a bump in early June at the cost of May. 36k/week? Ehhhhhh. From a source that religiously overtracks XB1?
I think mid 2015 at the earliest, unless Nintendo doesn't drop the U price. A lot more people would pick one up for a second system at $199. Whereas even at $299, the XB1 doesn't make a ton of sense as a second system unless you REALLY love Halo (and in that case you probably already bought one at $400-500).