PS3 and 360 were actually neck in neck in NA for half of the generation. Then in 2010, the kinect and xbox slim were announced and the rest is history.
What MS did do right was get hardcore to jump on early. Gears, Oblivion, Bioshock, Halo 3 and Mass Effect all in a span of one year. All exclusive. By the time CoD MW came out later that year, all the hardcore were already on xbox and as we all know they are the ones who spend the most money. They didnt even need the casuals. All the casuals ever did was buy consoles with kinect and then set it aside just like they did the Wii. Meanwhile the hardcore were replacing up to 3 xbox 360s month after month. I knew several guys who had at least 3 replacements in the early years. And yet the games were so good and so abundant, no one gave a shit.
I really hope MS goes back and realizes that its not about the hardware or the services or gimmicks, it's about games. Exclusives. It's about getting the biggest spenders on your platform. In your eco system. I dont see how both Sony and MS allowing the hardcore to go to PC helps them get into the xbox and psn eco system.