And this assumption is based on what?

This report is only based on a rumor, but for the sake of argument let's assume it to be true:

First, it says, "Controller’s total bill of materials and components costs no more than $50", meaning it could be as much as $49 or as little as $39.  Let's just estimate around $45.

Second, it's no secret that Microsoft makes a substantial profit with Kinect, as it is a one household purchase.  Even if WiiU is only able to stream intensive content (i.e. a full game) to two Upads at once, it could more than likely supply multiple Upads with simple content (maps, etc), not to mention just function as a basic controller for four player games, making purchasing several for one household a possibility.  Add to that the fact that the Upad is more likely to break or need replacing than Kinect, making its price prohibitively expensive in said cases a bad idea when Nintendo can still profit nicely at $70 or $80.  Even pricing it at $90 ala the Balance Board's launch price keeps it under $100.

Conclusion:  Nintendo won't price the WiiU controller at $100 or more.

I don't know ...

If I was in charge of Nintendo, I think I would bundle a game like New Super Mario Bros. Mii with the Wii U system and then bundle a handful of mini-game demos (like we saw last E3) with the Wii U tablet and sell it for around $100.

IBM want to be paid.
AMD want to be paid.
Blu Ray association or whomever they license off want to get paid.
Networking technology companies want to get paid.
Various other royalties also need to be paid.

Bottom line: Add about $30-50 to that estimated costing.

By those details, seems like it will launch at $299-349. Not bad imo.

$100 is still a bit steep IMO, but if it did come with software I might concede to that scenario.  The Balance Board with Wii Fit had no trouble selling at $90, after all.  The thing is, here, it would still be $10 more than that, and also the only way to get the Balance Board and Wii Fit (before there was a bundle, of course), was to take the plunge and purchase it.  Since every WiiU owner will already have a Upad, making the luxury of owning a second one that pricey may prove unlikely for many to justify since only certain games would benefit from it.

I still say Nintendo won't charge more than $89.99.

i'm going to have to go with this

Rumors galore! Cannot wait for this year's e3..

This is probably yet another not true rumor.

That being said if Wii U really only costs $180 to manufacture including that fancy touch screen controller than that alone would be confirmation that it will be severly underpowered.

Eiter way E3 can't come soon enough, I'm ready to get some for sure concrete details on next-gen.

You read it wrong, but is not your fault because the title is misleading. That is the rumored cost of the PARTS ONLY. The parts of a Xbox360 or PS3 right now should be around $80-$100, so this is almost twice the price IN PARTS ONLY, even if you exclude the price of the controller (in the rumor says it should be bellow $50) is still $40-$60 more expensive. Then you have to add manufacturing cost, shipping, advertisement, R&D done, profit for the retailers and hopefully profit for Nintendo, that is the reason they are pricing the console at $300.