There was an article on this site dealing with the Top 10 Conspiracy Theories of this Generation of Console Gaming.

One of the listed conspiracy theories had to do with the notion that video game companies had created scarcity in order to sell more of their product, and it cut down this notion that the companies had created scarcity to heighten the demand for their products.

Still, I think there is something to the theory, not that the companies created the scarcity, but that the notion that Nintendo and Microsoft did benefit from the fact that their consoles were difficult to come by at key times (Microsoft Christmas 2005 through Spring 2006 and Nintendo pretty much from the Wii's launch through two holiday seasons until the console became much more readilly available on shelves somewhat in 2008 but really not consistently until 2009) and that this did result in heightened demand for these consoles.

I believe that regardless of reason that since the consoles were scarce in these times and the scarcity of the products was reported on a great deal by the media and word of mouth among friends and coworkers -- basically these became the cool products to have -- that this generated quite a bit of hype for the consoles and have allowed them to enjoy quite a bit of the success that they have today.

What are your opinions of this matter?

I totally agree with that. Conspiracy or not, I am certain a stock shortage helped with impulse buys, as consumers would think that if they don't buy it now, they may not be able to later. And like you mentioned, the media coverage was free prime-time advertising for Nintendo.

I still don't understand why Nintendo couldn't secure additional manufacturing contracts for the Wii, unless they themselves didn't think it would sell so well.

If you increase hardware production, what do you do when demand is satisfied and sales drop? Now you have extra production capacity that goes unused, and is costing you money for just sitting there doing nothing. Nintendo certainly learned this lesson hard during the GameCube era.

Also, the Wii is made of lots of little components; in order to increase production, every component must also increase production, which requires coordinating with lots of parts manufacturers. The ability to increase production, is limited by the one component in tightest supply; a chain is only as strong as its weakest link.

I don't know, I meant it in a general term; that if there's a shortage of even one component, then Nintendo can't produce more Wiis than supply for that sparse component.  Also, a shortage doesn't mean a component isn't available, but that Nintendo needs to arrange for more of that component to come their way; and Nintendo has to do that with all of their parts manufacturers at the same time, which can take months to coordinate.

It's also possible, that all of the components can be easily gotten, and the real reason is the first one I gave, that Nintendo doesn't want to get stuck with excess production capacity that sits idle.

Scarcity isn't intentional.
They all have to not over produce as holding them in warehouses cost money.
And technology moving forward all the time. If you produce a year worth of electronics now and sell it a year later. You're paying too much.

It is also impossible to produce just-enough so we will see occasional shortages.

The production line will produce certain amount and will not increase or decrease due to a month or 2 fluctuation.