Final Fantasy VII had the highest attach rate ever for an RPG with 9.5%.
When FFVII was released the PS had not sold 100,000 million units. In fact, the attach ratio for FFVII was quite high when the game was released. Attach ratios don't work well on Sony systems because they sell over 100 million therefore making it impossible to have high attach ratios.
This has never been a problem for Microsoft because they haven't been successful enough to sell enough systems to the mass market and only supplied games to their niche community. Notice how sport games and shooters have high attah ratios on the Xbox/360 but other genres not so much. It's a measure of success that the Xbox brand has yet to achieve and that's why attach ratios are high on their systems.
If you only sell 20million units, obvious attach ratio will be better then a system that has 100+ million.
