With websites like nowinstock, that's not really surprising, is it? It removes the friction of people having to browse around.
No matter how big the supply, as long as demand is higher, these kind of websites pretty much guarantee that cards will sell out immediately.
Yeah like I said here in UK one of the most popular retailers is doing better at launch than 970, which is quite incredible and shows Nvidia knows their market very well.
But even here we have sites that make it very easy to check the main retailers, even Nvidia makes it moderately easy for UK as it lists models and UK sites-retailers selling, albeit with no stock info but provides easy access to a diverse range of major stockists.
And still quite a few places still have various 1080FE in stock now, which for North America seems very different with stock out.
If I can find a few major retailers with 1080FE in stock (not all but not difficult to find) with sales for at least one better than 970 launch (I would assume the trend would be across all UK stockists), then one would expect a similar situation in North America but maybe sales there are better than even that.
As you say we need more info, but strange can be that selling patterns and warehouse stocking-logistics are unusual, and exacerbated by the huge buying interest.
Just to add as Carsten mentioned there is a fine balance for manufacturers between internal manufacturing line-stock levels and storage, it has been ages since I was told about it but there is a formula many of the large international manufacturers use to calculate how efficient their line (manufacturing and logistics) is, and deviations from the figure means business-manufacturing efficiency is down for that product.
For a new product they would have some kind of financial-sales forecasting and probably based upon 980/980ti with a buffer for additional interest, but I doubt even Nvidia expected the 1080 to do better than 970 in some regions at launch (key point 1st several weeks).
The 1080 would be deemed a small footprint enthusiast product, so they would not go nuts producing much beyond their forecast, otherwise if sales were not strong the manufacturing line would need to be slowed down including purchasing of components required from 3rd parties to build the product, impact this has on the logistics side-shipping batchment process,etc.
AMD will have a different forecast challenge with the 480, but its sales will still be more sustained after initial launch due to larger demographics of potential customer due to targetting mainstream product.
Cheers