Well, look at the launch of the current gen. Xbox One sold well! Really well! It was the 3rd highest launch ever at the time (if memory serves) in spite of them absolutely butchering their reveal and Sony's more capable, cheaper machine and all the good will in the world.
They could have killed a puppy live on YouTube and would have been applauded. In spite of this, ps4 didn't double xbox during the launch window.
Sony isn't going to have that luxury next generation. While they're very likely to sell more next generation, it isn't written in stone. AMD would be fools to back one horse over the other when they already have both in their pocket.
Both consoles where sold out during launch and until new years. Would they had more stock then we would have seen the ps4 more than double the x1. Also remember the ps4 launched in more markets so that alone would have given them a big plus. Also remember the x1 was readily available after the holidays in jan. The ps4 was still sold out for the next few months. The demand was way higher for the ps4 but the stock was not available.
It takes genuine talent to see greatness in yourself despite your absence of genuine talent.