It's too bad that we don't have enough data on weekly sales for PS2 games. Those would be interesting to look at.
This is the reason I usually say that legs (good legs or bad legs) are "casual" or mainstream users buying the game. They walk into a gaming store, ask for something that is good, and get a well known game. Thus better games usually have better legs. Or they go into Wal-Mart or a similar store and look at the games in the display cases, see something that looks good, and they get it.
Thanks for putting it together. Doktor85 has a point though with advertising, so of course this formula of using the first 10 weeks as the hardcore users and everything after as mainstream users has it's shortcomings, and 360 games are usually very heavily advertised, so it's more likely that more sales will come during the first 10 weeks compared to other games... and it shows with the 360's high "hardcore-ness."
