I think this has been known as being an issue for some time. With XB360 I think that they designed the OS software, hardware, and network infrastructure at the same time, it was a system designed to have features such as cross-game chat from the start, Sony simply didn't do that with the PS3. Without getting into the split RAM pool, as they reduced the OS footprint, they simply gave it to developers rather than reserving it for features such as this. The PS3 can do it no problem, it's simply not mandatory. There is a load of stuff in the PS3 GAMEOS such as playing your own music in-game, directly uploading replays to YouTube, using the web browser in-game, etc. it's up to developers to decide whether they want to lose RAM to do any of those things. GT5 for example has custom soundtracks, but it was also supposed to have the YouTube upload stuff but it was taken out because there was in the end not enough RAM to support it.
RAM was their biggest mistake, they should have gone with 512 XDR and 256 of the VRAM but they were bleeding money on the machine at the time, and adding more 256MB of XDR RAM would simply have made it worse. Cheap as chips to do now of course, and if a new model had that then those models could do it, but what's the point at this stage of the game? Yeah, you'd be able to pull the web browser up and post on RedCafe whilst playing a game, but why bother? You still couldn't do cross game chat with people playing on the 50m machines already out there. BTW, the cost increase isn't simply down to the cost of the RAM, it can cause all sorts of other problems from board complexity, power use, latency, heat and cooling solutions, etc.
Why did Microsoft use a standard DVD drive instead of HD-DVD which they were trying to push? Same thing - cost, but now you're seeing games over 2, 3 or 4 discs. BTW Microsoft were originally going to release XB360 with only 256MB of RAM. Now that would have been a disaster.
