The legs contribute is L * I(w). The L factor is still different for each game and each version.
Higher L means higher share of release-time-indipendent shoppers that are likely to buy a given game. It could be that L is approximately the same for GC and Wii, though I actually think that it was bigger on GC (more "core" gamers also means higher L).
The PS2 actually looks like it has a smaller L indeed having a bigger I. That lower L accounts for install base demographics ( at that point in its life I guess the PS2 was even more "casualized" than the Wii) and for other factors ( the carry-over crowd from the GC to the Wii is more likely to buy a RE4 copy than the average PS2 owner, basically the F and N factor for them are so flat to contribute to L )
Basically too many parameters to draw a resonably subtle conclusion, but the general shape of the curves is not unexpected.







