Point number 1
As you all can see Tomb Raider has almost identical legs with both versions. What it means is that the difference between two platforms starts to show after 10-15 weeks, however the gap takes a status quo position after the first holiday season.
Point number 2 (and this is a major one)
Tomb Raider on Xbox 360 is selling on par with Rise of the Tomb Raider on Xbox One, or is it? One important thing that you might have missed is the holiday bump which is going to boost Tomb Raider on X360 by about 300,000 units sold.
Why is this important you may ask?
As you may have noticed this is a cumulative sales comparison, but the launch dates of TR and ROTTR vary greatly, what this means is that ROTTR won't be receiving a holiday boost in another ten weeks on this chart since it basically launched into the holiday season last year.
Keep in mind that when the bump eventually comes it won't have as much effect because it is the second holiday season for ROTTR while the huge bumb for TR is the game's first holiday season due to its Q1 release back in 2013.
And this is why release dates do matter when comparing how fast the games in comparison are selling.
So in the end ROTTR is NOT selling at similar pace to TR (X360) at all.
Now discuss...