Your post is filled with all sorts of fail.
The only thing that will usher in the sort of disparity you're expecting is a significant price drop on the 360 with Sony doing absolutely nothing in return.
Gears of War 2 and Fable 2 are titles that will sell really well, but they are also titles that will cater to the audience that already purchased the Xbox 360.
Not only that, but Sony has the benefit of Blu-Ray ramping up this holiday season with some pretty stellar releases like The Dark Knight and Wall-E, not to mention cheaper HDTV prices and more promotion of Blu-Ray in general in stores. Given that the format war is over, I think Blu-Ray will provide a decent boost this fall.
Further, Sony has a strong lineup of its own. Resistance 2, MotorStorm 2, and Little Big Planet are great titles. Arguably, if there's any game that has the ability to capture more PS3 users it's Little Big Planet. Like Gears of War 2, Resistance 2 is a title that will sell to the hardcore fanbase.
What it comes down to is that the PS3 is perceived as a MUCH better value to those that haven't juped into any system yet. Blu-Ray and the release of solid content has solidified this view. Before, consumers felt they were paying a premium for a feature (Blu-Ray), that may not be viable in the long run due to the competition from HD-DVD.
Like I said, the only thing that will stop the PS3's current trend is a price drop from MS. The software lineups could each be argued any which way.