Canova said:
which is what? I don't know what you're trying to say here
The 360 has sold more software than the PS3 (in the US).
The 360 has sold more software per user than the PS3 (in the US).
This does not mean that for every single multiplatform game, the 360 has sold more copies than the PS3, or the 360 has sold more copies per user than the PS3.
For some multiplatform games (Virtua Fighter 5 for example, actually fighting games in general) the PS3 has sold more. For some multiplatform games (some of those listed for example) the PS3 has sold less overall, but more per user. For some multiplatform games (Borderlands for example) the 360 has not only sold more copies, but more copies per user. The ratio of multiplatform games in each category has varied over time, so even if you assume the PS3 has a better attach rate than the 360 for every game released in 2011, it still doesn't change the past times where that wasn't true.
Tie ratio is also impacted by exclusive software on both systems. If Halo 3 sells 6.5 million copies in the US and Killzone 2 sells 950k copies in the US, Halo 3 is contributing more to the 360's tie ratio than Killzone 2 is contributing to the PS3s.
Finally, while tie ratio generally increases over the life of a system, attach rate generally decreases. Nothing on the PS2 broke a 25% attach rate lifetime and only a small handful of games broke 8-10% lifetime. This doesn't speak to the tie ratio because there were so many software SKUs.
Canova said:
The only way 360 has better tie-in ratio (if infact PS3 has better attach rates in most software measured) is if 360 has more retail software. Which it is, since it's in the market longer
It's not just being in the market longer and I really don't see what you're failing to grasp here. You are taking 9 multiplatform data points in the last year or so. You are extrapolating this to cover 300+ multiplatform titles across 4.5 years as well as all exclusive titles during that period as well as all titles on the 360 from before the PS3's launch. You are then acting surprised when that extrapolation is incongruent with reality.