I dont see either company giving the other a year headstart.
Its just so damaging to the console thats a year late.
Im sure both companies have a good idea when the competition is planning on releasing.
This is reasonable, but I'm curious what Microsoft might be thinking.
The accepted wisdom seems to be that a) they will launch at the same time as Sony and b) they will aim to out-power PS5, if possible, which, sans a significant price differential, seem mutually exclusive, unless they can produce a superior design for the same price. This is possible for either company, but ultimately it comes down to chance which is better, all else being broadly equal.
So if the current wisdom is if Sony hit 2019, so will MS, or if Sony hit 2020, so will MS (to avoid a debilitating difference in install base), how can MS be sure what Sony will do? My point here is that MS may be able to be fairly sure of Sony's launch plan, but if they aren't, and if they want to avoid being a year late, surely they have to aim for 2019?
This might actually be a better strategy for them - if Sony hit 2019 then MS are day and date. If not, they have 6-12 months in the NG market alone. Certainly this might give Sony a later power advantage, but that's not certain and may not be all that significant. I don't think we should discount that MS may attempt to be disruptive and chase the success they had with the 360 approach, and I'm not convinced a new Xbox 2 years after the X1X is all that damaging if the attraction of next generation games is sufficient to pull in the customers. Ultimately the X1X is a souped-up Xbox One and is unlikely to ever play NG games, so if you want NG games, you need NG Xbox. It's a PR problem, but certainly not insurmountable.
If MS did get out ahead of PS5, they get all the excitement of NG and a user-base of millions before Sony are out of the gate. The down-side is a potential power differential, but that isn't necessarily a huge problem. I don't think this is a likely scenario, but it is possible.
I just think we can't assume that MS can know when Sony plan to launch (or vice-versa), or that they are utterly wedded to we-must-outperform-the-PS5-come hell-or-high-water. Doing the disruptive, unexpected thing might be what they need to do.
At present I expect both PS5 and Xbox NG in 2020, or both in 2019, but perhaps we shouldn't be so convinced that either company can be certain what their competitor is planning, or that alternate approaches are untenable.