You do realise Nintendo pretty much sold every Wii they shipped out of their warehouses right? Considering the
Wii in its first 12 months easily sold twice of what the
PS2 (the forever bell curve in console sales dominance) did in its first 12 months of sales.
While admittedly, Wii got two Xmases with its first 12 months, but if you arbitrarily took the Wii's first 12 months that only gave it 1 Xmas (April07-March08), it still outpaced the PS2 in terms of sales. What the Wii did was unprecedented and the demand would still be there, even if Nintendo would holding back any stock
ANY STOCK AT ALL. There was literally no reason for them hold back stock when they could be sold to sell software, ie where the real money comes in. if they held back any stock at all, they did an incredibly lousy job at it; but demand for the thing lasted for years before it finally tapered off years later.
If any hardware supplier is to be called out for holding back supply to artificially inflate supply, it would be Sony with the PS2 since they were bleeding out their ass selling the thing for 299.99 at launch, but since it was the successor to the PSX, they will always have a line of customers. The demand for the box was enough to help permanently kill off the much cheaper, just as capable (at the time), and with a much better library Dreamcast.
Whereas Nintendo profitted with the Wii right at the start. If you're any sort of businessman with brain, you sell and fatten up that bottom line.
If there is a shortage of WiiU after launch, then you better believe it'll be the same reason why all new hardware will have shortages (building new hardware configuration is a pain), but it will not have the shortages the Wii had, which mind you lasted for years, longer than PS2 shortages.