I don't think they will personally, I'm expecting both to release Holiday 2020. Launching later just to get better specs seems like a mistake, it's usually the cheaper console that wins, not the more powerful console. PS4 was the exception to that rule, mainly because MS shot themselves in the foot at the start of the gen.
I think people underestimate how fucked the Xbox one release was. Most European countries didnt have it for a few months. Getting one was a fucking hassle. Then you had the Kinect bullshit making the console more expensive then the PS4. Dead rising 3 was the big opener with it but hardcore Dead rising fans hated it so its hottest release got a ton of backlash (I personally thought the game was fine not as good as 1 or 2 but fine) It was just a huge mess all around.