You're making some hellishly big assumptions here.
1. We don't know how profitable or loss making the Xbox 360 is. With the PS3 we have one loss maker, the PS3 mixed in with the PSP which likely at least breaks even and the PS2 which is still almost a pure money spinner. With the Xbox 360, we have a profit maker -> Xbox 360 mixed in with a whole bunch of loss makers and R+D slush projects. With the Xbox 360, they stated previously that they broke even with accessories and with the recession looming the component and shipping prices and the fact that the average sale price is $290 in the U.S.A its quite likely that the current console sales net them a small margin. Also the losses this last financial year were not attributed to the Xbox 360, it was R+D.
2. You're assuming that the PS3 WILL drop to $299. Heres some magical news which you probably don't want to hear. If Sony lowers the price by $100, they will have to make up any losses on the extra consoles that it sells. If Microsoft matches such a price cut their sales won't rise nearly as much and it will end up costing them money. So how likely is it that Sony will be able to get an unanswered price cut of $100? Quite unlikely actually and since Microsoft has already stated their intention to hold the PS3 to third the chances of them making such a drastic drop in retaliation are very good if not expected.
3. Not all the games you listed will come out in the next 7 months. Many people expect a lot of the games you listed to come out in 2010.
4. During the Holiday quarter, the sale balance between others and Americas shifts from 110:100 to the Others to 100:110 Americas and this is the Xbox 360s strongest region. Also since a much more casual userbase starts purchasing consoles, the price is an even greater facter than ever before. A $150 Arcade is still half the price of a $300 PS3 and during the silly season the Xbox 360 has shown a great advantage over the PS3 in terms of sales. For example last Christmas the Xbox 360 was hugely above the PS3 in terms of both ratio and absolute sales. The Christmas before that when the PS3 had its $200 price cut, the Xbox 360 sales = the PS3s sales. Theres still a good chance that even a $50 price cut to a $100 price cut would seal an advantage for the Xbox 360 during the Holidays.
Tease.
