...or a year headstart with pretty much no competition. 

ive said it before and i truly honestly believe it, if the Xbox 360 wasnt such a turd in the reliability market it wouldnt have sold as good as it did.  i personally went through 3 before they extended the warrenty, which means i bought 3 xbox 360s when my 3rd one died is when i got it repaired by MS and then sold it i was done with the 360 at that point.   The same goes for about 10 family members where they all bought at least 2 of them if not more and a good chunk of friends i have did the same, i know only 2 people who still have working launch 360s and those people didnt play it much.  ill bet the same goes for a majority of 360 owners, this in my opinion inflated the numbers drastically, i remember reading somewhere in 2011 that it was estimated about 30% of the 360s sold at that time were second or third replacement systems for people.

and to those that say ms replaced the majority the answer is yes but only after 2 years of the problem being around my first 360 died roughly 3 months after purchase my second 360 died about 6 months after that my 3rd one died right after they anounced that they will do free repairs on the system in early 2007

XOne will never achive the sales of 360 in any territory. 360 was simply a better console.

Xbox 360 was so successful that it is very hard to get similar sales. That is the main reason.
In my opinion, even PS4 won't sell as good as X360 (In US).

Not it wasn't. Its unreliabilty alone made it much worse than X1. 

Agree. Things 360 had last gen that the One doesn't have or won't give the same impact.

1. One year headstart
2. Kinect ( most people don't care about motion control nowadays).
3. Better multiplatform.

It will not only NOT dominate but it will also sell less, DEFINITELY.

One thing people do not realize and wrongly assess is the brand power of xbox. It just is overblown in people's minds. Last generation x360 sold as much as it did because of

- price point (it was $299 for the entry model)

- PS3's late arrival

- spiraling network effects (people bought x360 because their friends bought x360)

...and NONE of these advantages exist today. Although there is some good inheritance from the 360 era, the bulk of the x360 users are ready to jump off ship as long as the other system has the games they are looking for and their friends have the same system.

The network effect is already in action. There is no such thing as ps4 hype, which is a very short sighted statement. If you go thru my estimate history, you'll see ps4 is doing exactly as expected. It is just most of the platform neutral people (probably over 60% of the console crowd) are now buying PS4 instead given that it is/was cheaper, it is selling more, it has way more consistent policies, it is more game focused, and more readily available (and of course it is more powerful).

This is also why XB1 looks more popular in the US among the consoles fans who are socially interacting but in actual sales, ps4 takes the lead hands down because for a more relaxed casual gamer, ps4 is hands down the default choice. Believe it or not those more relaxed console-neutral gamers out there are the majority and those can swing them wins the generation. So, regardless of what Microsoft would do, Sony will win this generation even in the US and UK, their strategies (such as buying exclusives etc) will have a limited appeal, as console-neutral crowd overwhelmingly prefers the PS4.

Halo and Gears of war say hello not to mention the trailer load of exclusives coming out.

When these games come out Xbox One sales will take off, especially in america.

Xbox 360 has come very close to becoming the number 1 selling console in the US of all time, I don't think anybody was expecting Xbox One to come close!

It is sad an it annoys me that people still use to dare the word 'NEVER' on VGchartz...

As an old member who came back to this site I can't stand the word 'NEVER' anymore because It was used in so many projections in the past that in retrospect were dead wrong...

Some of the oldest member all will remember the famous  'The Xbox 360 will not or Never pass 50 million sold'.   That thread was like made two years after the release of the console, it was in that time that people laughed with people who believed it can pass 50 million....And if you dare to say that PS3 will pass it aswell you must be the town idiot....   or one of the other 2500 threads with never in the title that were so wrong.... 'Kingdom Hearts 3 will never be on a playstation/xbox console because of the success of the Wii' or 'Final Fantasy XIII will never be on X360 because of XXXX'

While Xbox one has been released in less countries and has competition from day one it has sold better than Xbox 360 which had no competion and was released in like 20-30 countries more = so we can assume that Xbox one 'never' will be so succesfull as Xbox 360...

The Xbox 360 was released for 2-3 years and people assumed it would not reach 50 million and they were dead wrong....so what is the chance of you being right of assuming something after 10 months of a consoles release....  

I don't say you will be wrong but I just want to make it very clear that people should not jump to conclusions to fast...it is only 5-6 months ago that people believed PS4 will destroy Wii U sales in Japan....Today those same people will have a huge party if PS4 weekly sales can beat Wii U weekly sales in Japan again...