None of those games receive more marketing dollars than Halo and it's ok ?
The difference in my mind is the PS3 has a hell of a lot more to prove to third parties.
Talk Halo for example. CoD4 and Halo 3 launched in a very similar window, albeit with a month or so of spacing. Both games sold amazingly well - not too far off each other in total sales IIRC. The userbase of the machine - largely core gamers - had room for both games in their market. This was evident every month of the year in 2007, with 360 having "big releases" every month which sold very well. In the end, CoD4 was a massive success on 360 despite the fact that Halo 3 was still fresh in everyone's memory.
PS3, as you've said earlier in the thread yourself, is "diluted" (your term) in its userbase by having people buying the machine just to watch movies. On top of that, there are less machines out there in the first place, making the smaller group of potential buyers even smaller. It also doesn't have the history of supporting big releases to match its big exclusives in the same window that the 360 does.
Now look at the situation with Resistance 2 vs COD5. CoD5 is being released one week after Res2. Res2 is massively hyped by the Sony fanbase, which have a strong history of favouring exclusives over multi-platform titles. Lastly, as you yourself said, Sony will obviously be pushing their own title as the game to purchase over CoD5 when it's released at the same time. They will market their own title, meaning CoD5's marketing has to be pushed even harder, giving them less money in profit down the track. The way you worded it was actually quite appropriate: "Yes, there is a clear conflict of interest."
MS has done a hell of a lot for third parties in terms of stimulating support for the system. People on message boards cry "money hats" every time something comes up, but the reverse situation is Sony saying they won't "buy" support for their system while actively competing for their dollar. As a dev, what would you do? Add this to the relative ease of development on the 360, vs the complexity on PS3, resulting in poorer looking PS3 versions of multiplatform titles, plus having a smaller user base leading to lower sales, and I don't think anyone should be surprised at the current situation with third parties favouring 360 at this stage.
You obviously understand this situation quite well, given you've made much the same points as I'm making here earlier in the thread.
Edit: I guess to make the point I'm making painfully clear: what do you think November's NPD's will look like for Resistance 2 vs Call of Duty 5 PS3? How does this compare to CoD4 360 at the same point last year? If you were Activision, how do you think you'd feel about that?