If 100% of MGS4 sales were attributed to current PS3 owners (they weren't), then 25% of the PS3 base now owns that game in Japan.
That's awesome for MG4, but sad for the PS3. Why? First of all, no sales spike leading up to the title. At 10,586 units sold last week, the anticipatory buy-in was a resounding "meh." That is the first red flag.
Of interest:
1. The pre-MGS4 PS3 LTD is 2,079,104.
2. MGS4 first week sales (90% of LTD) were 465,000.
=====================
(% of base that bought the game) = total increase in PS3 hardware sales
100% = 0
90% = 46,500
<<--Total sales this week somewhere in here
80% = 93,000
70% = 139,500
60% = 186,000
etc. = etc.
Hypothesis:
If PS3 unit sales are less than 70k for the week (they will be) [edit: famitsu says 70k, but i'll stick with the argument], then that means that between 80%-90% of MGS4 sales were sold to current PS3 owners.
That also means the PS3 is now owned by the majority of people that would ever buy the system for such a game. Now, maybe it isn't that big of a game in Japan and I'm blowing things out of proportion, but if/when 2/4ths of the PS3's biggest games (Gundam, MGS, GT5, FFXIII) are already out and they aren't generating more than a handful of console purchasers, it means we're nearing market saturation on the product.
Yeah, it's a bold statement. But for Sony, now is the time to be bold and make a move for the PS4.
(edits for clarity)