I think that 1million - 1.5 million are Famitsu's LTD predictions for FFXIII. Their first shipment (first week?) predictions are 800K-960K.
A 50%+ attach rate for FFXIII (or any game for that matter) sounds pretty high indeed, i agree. But to take one example regarding the main Metal Gear Solid games. Here are how much they sold in the first week and how big the console install base was at the time when the games got released (FW = first week software sales) :
- Metal Gear Solid 2: 456,747 FW / 5,588,723 PS2 Installbase
- Metal Gear Solid 3: 487,156 FW / 15,678,355 PS2 Installbase
- Metal Gear Solid 4: 476,334 FW / 2,177,825 PS3 Installbase
The first week software sales are pretty similar eventhough that the MGS2 and MGS3 had a much bigger installbase. MGS2 and MGS3 has a
bigger LTD compared to MGS4 though, but the first week sales are rather similar at least. Unfortunately i dont know where to find numbers for MGS1 and how big the Playstation 1 userbase was when MGS1 was released.
There was not a 50%+ attach rate senario with MGS4 and with the PS3 though, so it might be a quite different senario when we talk about a 50%+ attach rate senario, but i just wanted to mention that the installbase might not always matter
that much in some cases, at least in my opinion. So who knows how much FFXIII will end up selling even if the PS3 installbase isnt exactly that high, i think it shall be interesting to see how much FFXIII sells at least