On the subject of: "is the Xbox One selling better than the Xbox 360 did?", I made the following chart:
So, yes the Xbox One is still around 800k units ahead of the 360 launch aligned. But by breaking it into periods you can see that the One had a fantastic launch and has since slowed down a bit relative to the 360.
I've been thinking about this for a bit and here is my theory for the sales trends we've been seeing. First, the data:
PS4 sold more in its launch month in the US than any console in history.
In 2014, PS4 did not perform as well and was routinely outsold by consoles like the PS2, Wii, and even the 360 in similar timeframes.
In its first September, PS4 sold more units than any other console's first September.
Now, I believe there are a couple of factors that attribute to this sales curve:
1. Supply at launch is much better. That means you will see more units sold at launch and deflated numbers after launch compared to past consoles. You see this with both the PS4 and the Xbone - both had huge sales out of the gate and then dropped off a cliff during the slow months.
2. Because of the internet, consumers are a lot more aware of releases. Take July and August of this year, for example. Many buyers waited until September to buy the PS4 because of the Destiny bundle, so you see deflated numbers for July and August, and inflated numbers for September. This is because many more potential buyers are aware that a white Destiny bundle was coming due to the internet. People watch E3 streams and announcements now when 10 years ago that wasn't the case. Forums such as GAF and gaming sites, podcasts, further propel these news. What this means is that sales will be more concentrated around big releases than ever before.
3. Consolidation towards large AAA titles. Because of increasing budgets, we are seeing fewer retail releases, and more focus on a few, AAA titles with larger budgets than before. This will further lead sales to concentrate in a few games and specific months.
You can see this behavior in Japan as well, where games like MH4G and Youkai Watch 2 open with 1m+ week 1, but by the time you get to the #10 game it's selling sub 10k.