If a system is as popular as the PS2 was, developers will stick with it and be drawn to it regardless of how complex or difficult it is. On the other hand, if a systems isn't selling too well and is very complex to develop for, developers will be hesitant to put in the time/money needed for fear of not making a profit. An example of this is the Saturn. The Saturn was extremely complex when compared to the N64 and PS1, and when it didn't sell, developers jumped ship like crazy.
I'm not trying to imply anything about the PS3 or its future. I'm just saying the difficulty of development is indeed a factor, but it's a factor that becomes less important as sales go up (more potential costumers = better chance of good investment returns), as was the case with the PS2, and more important when sales are low, as with the Saturn. Likely the PS3 will land somewhere in between since it doesn't look to be as doomed as the Saturn nor nearly as popular as the PS2.







