At this point in time, one can wager that unless Microsoft finds component exuberantly high, the company would want to start things at the $399 mark.
MS claims their GPU has 6tflops of computing power. The recently released 1070 has 5.8 tflops of power and costs 380$ on its own. It also has a slower bandwidth than what Microsoft advertised for the Scorpio. It's WEAKER than the Scorpio for 380$.
The scorpion will most likely use AMD's answer to the 1070/1080, so sure, I expect more bandwidth and 6tflops at a lower price. But even dealing directly with AMD, I'd be surprised if MS could get those stronger cards at 300$ compared to the weaker cards at 380$.
And if MS spends 300$ on the card alone, the console isn't gonna be 399$. Only way this would happen is if the GPU is not actually 6tflops OR if MS sells the consoles at a loss just to gain a piece of the market. And I could see this happening, I could see MS willingly losing money just to gain a part of the market. That's what they actually did with the original Xbox, selling consoles at a loss.
But that's not Microsoft being geniuses. That's just paying your way to a stalemate.
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As for the sales: it's a bit funny to celebrate the sales of a single week, and
only in the UK. In September, too.
In 2016, Sony actually increased the gap between the PS4 and the Xbox One. The total sales (since launch) are 43m PS4 sold and 22m Xbox One sold, meaning that for every Xbox sold 1.9 PS4 were also sold since launch.
But in 2016 exclusively, the sales are 6.7m PS4 and 2.6m Xbox One. That's
2.5 PS4 sold for every Xbox. Sony increased their lead on MS, instead of MS gaining ground on Sony.
Sony is releasing VR in October (if I got that right) and the Pro in November. Their goal is obviously to ride the wave of November sales all the way to the bank. But if MS wants to turn things around, they need a bit hit in November to take the wind right out of their sails. To make sure PS VR and PS Pro are both dead in the water. This is their opportunity to change the momentum.
For the time being, it's the opposite. Sony is increasing their leads in hardware sales and maintain a lead in software sales (in 2016, 1.97 PS4 game sold for every Xbox One game sold).