Apple buys a lot of components from Samsung. There is literally no reason whatsoever that would cause Samsung to be unable to undercut Apple in prices.
Samsung walks a tight rope. Whether to sell components to Apple to make some profit, or build their own tablets and make a huge amount of profit, or go bust. I would love it if Samsung could make iPads, too. So that the diversity of the ecosystem can be maximized. The strongest would survive, and consumers win.
Please provide evidence that the "OS" will cost $99. As of today, most OEMs pay between $30 and $50 for a copy of Windows, and I don't see that going up anytime soon.