Yes, the ps3 is getting plenty of 3rd party support especially more than before, but the 360 still gets plenty of support from 3rd party. There is exclusive content in the 360 version of Homefront, Child of Eden releases first on the 360, Crysis demo was on the 360 before any other systems, Beyond Good or Evil released on the 360 several months before psn, COD DLC first, etc.
the funny part about your examples it that Portal 2 is selling better on 360 reguadless and LA Noire will probably sell better on 360(judging from pre-order numbers). Mortal Kombat is the only 3rd party game that you mentioned with an extra goodie that will sell better on ps3, but I'm pretty sure it would sell better reguardless. If you didn't know the 360 version of Mortal Kombat has some extra goodies also like the Pit stage is exclusive to the 360, we can use our avatars in the king of the hill mode, 360 gets an extra mode called puzzle kombat, and scarlet (DLC character) will be free on the 360 for a limited time while ps3 users have to pay.
I want to know what this has to do with the topic of the thread?
I'm not going or trying to pretend 360 doesn't have good 3rd party support but they other guy said that the reason they had it was because of lack of many core exclusive (thus relevant to this thread) Yet sony is gaining the 3rd party support in the year in which they have the most good 1st party exclusives so he's obviously wrong