Scorpio has a bit of a different advantage, besides being more powerful. A LOT of people switched to Sony this generation. If the Scorpio is executed properly (price point, power, future games), Microsoft could potentially persuade a lot of PS4 owners to switch back to Xbox,
Where the PS4 is already the dominant console, by a fairly large margin. So you are going to get the core gamers to upgrade, but Sony isn't going to really going to attract the smaller XB1 install base to switch to PS4.
I feel that Microsoft has the chance to really knock it out of the park, but everything has to be perfect. I remember seeing Phil state that they are moving away from marketing deals, so I am really hoping they are funneling that money into creating new IPs.