LOL why? The X1X is no threat to ps4...at all, not even at the same price, not globally. Sony can leave it at 399 and coast if they want.
The X1X, if proven much better (hardware wise of course), can be a threat at just 100$/90 more. The base PS4 is the bigger threat (can easily be found for around 200 with one or two games here), I suppose they didn't do r&d on a new hardware just to sell the older one more. They're going to push the Pro a lot more now that MS unveiled their midgen console.
Paris Games Week is the week before X1X is released, that would be a perfect time to do a price drop.
Forgot about that. There's also Milan Games Week (29-30th september/1st october) but they have never done announcements/conferences here, so PGW will probably be it.