Because Sony only shipped in NA first week.  If MS strictly shipped in only NA instead of 13 countries they would have sold the same amount.

I explain then...

Suppose you have 1 million in stock, only for 2 weeks, being the last one BF week. If you split that in equal numbers you sell 500k one week and 500k the other one. Now, imagine Microsoft can put 500-600k units in NA for BF minimum. If you were Sony, would you risk losing BF sales or you prefer to sacrifice the first week, one that no one cares except us here, to have a complete million just for BF to trounce your adversary??? That's my point.

And i'm not saying sony will sell 1 million nor Xbox One will sell 500-600k, it was just examples...

No they wouldn't have

I don't think you're understanding the argument being put forward.

If MS had turned all of their early manufacturing towards making NA systems, and shipped only to NA in the first couple of weeks, they would still sell the same number of consoles they did across 13 countries, because the same number of consoles would be manufactured, but they would all be sold in US and Canada, and thus would match the PS4's launch numbers in the region.

It's certainly a debatable claim, but not one that you can dismiss outright. The question to ask is, did the Xbox One sell out its first shipment, or are there some Xbox Ones still on shelves?  If the former, then the claim is likely right that Xbox One would have sold just as well as PS4 given equal shipment numbers, while if the latter, then the claim is wrong.

It will rise huge when the stock is available. I don't think you get how this works.

Sony produces only about 1 million PS4 units per month. The console launches are two weeks apart, meaning they've only produced about 500K PS4 units in that timeframe. They have to send some units to the USA, but support their main launch first which is in EU this week (just like NA was 2 weeks ago). So Sony releases about 100K units to ship to North America, and has about 400K units left from their 2 week manufacturing period. It was suggested that EU gets 1.2-1.5 million units week one (if none are diverted to NA), which is on par with the NA first week support (1.1 million). So EU to complete their quota of 1.2+ million units still needs 800K-1.1million units that it hasn't produced, and this comes from the backlog from pre-NA launch manufactured PS4 units. And this week which isn't shown for the EU region, Sony has to ship some units to the NA region again. Expect only 100K units yet again, as their focus has to be a strong EU launch.

Taking the 100K hit next week into consideration, EU region will get/sell 1.1-1.4 million units. These periods are known as hard-launches, as about 90% of a product goes to a major region for the initial product launch. This varies by strength of region and EU is Sony's strongest region. After the hand launch you will see the units per-week increase, but you're right it will not be by much. Half will flood into the NA, and half into EU. 1m per month (divided) by two main regions is 500K units. 500K units split to 4 weeks and you get potential of only 125,000 units plus the backlog pre-launch unit stock still kept strategically. What it means is we're looking at 300,000 units shipped to NA every 2 week period.

They would not have sold out all consoles at launch if they only sold it in NA like Sony did. I know for fact that you could walk in Gamestops in both Dallas and Pitt and get and Xbox One without a preorder. I also know Best Buys in Philly area were still selling Xbox One after the first 24 hours.

So adding 4-500 K into the NA launch would mean no sold out since they really didn't do so to begin with

Because Sony only shipped in NA first week.  If MS strictly shipped in only NA instead of 13 countries they would have sold the same amount.

I actually wish that they would have two, because the old systems are going to be huge this holiday still. Pain to have to go and search out they're sales.

But life is full of change.