The big problem with delaying it any further is that PS2 is going to take a while to die down, so if they released it a year from now, all that would have happened is that it would have just taken an extra year for that to happen. Good for the Sony brand, bad for early PS3 sales. Beyond that, there are also concerns that a bigger headstart would provide Microsoft with even more support, though I don't believe any headstart would be insurmountable in terms of sales.