Marketing will be Scorpio vs PS4 Pro. It's largely irrelevant what the Xbone S can do.
Sure, people who want a 4K Blu Ray player and don't care about the 'next gen' exclusives on the Scorpio won't care. But what about people who are looking to buy either a PS4 Pro or Scorpio? Could easily sway them.
No it isnt irrelevant because the Pro and the XBOne S are out right now - rather than 6 months time. So anyone interested in a cheap UHD player is looking now, rather than waiting for a more expensive console than the S
(not to mention all the players from general electronics companies that compete on price with the Scorpio when its released)
Anyone interested in (just) a console wont be swayed either way by the UHD player (or at the most on a minor level).
Highly unlikely to sway a significant factor in 6 months
I can only see them holding out that long if they reaaalllly want to use Zen+, Navi, and HBM3 in a 7nm SoC.
If Sony poorly execute their exclusives library, and/or the Scorpio + Oculus is seen as a lot better, and/or cross platform games run a lot worse on the PS4 pro; then they may be in for poor sales until they bring out their 'real' new console.
firstly thats a very big "If" , no way of knowing that either way right now.
Baring in mind that even now you are talking about a 4 Pro + PSVR = approx £700 (admittedly camera and controlloers are a little more on top) vs Scorpio + Occulus more like £900 - £1000
(as far as I know Occulus is £600+ , maybe less once Scorpio is out to buy) - thats a significant difference which again will put off a lot of casual gamers unless they already have a lot invested in the MS market place (but again this is unlikely given we are talking about "casual" gamers).
Also baring in mind that MS would have to sell the same amount of Scorpio's as they have in XBOne's to date to even challange what PS4's have sold to date without taking into account any PSVR related sales to come on Sony's side.
Either way its not necessarily about technologies that are talked about now that Sony are interested in for PS5 - it could well be something totally new / or some kind of hybrid parts that dont appear anywhere else.
Personally think PSVR is good enough to sell a decent amount of PS4Pro's (while maybe not blowing the market out of the water) to keep Sony going for a reasonable length of time before PS5 is released
Remember Sony also have to see how the market takes VR itself, it may end up being a donkey like 3D or it could be HD which has basically been a natural progression of what came before. This is going to take time without even considering how much work may be required into developing hardware and software for the next stage of VR (if relevant , a big step will be required to hinge a whole new generation on it).
edit - I cant think of any console bundles that have included items from a completely seperate manufacturer (OR is Facebook I believe). Of course MS has the purchasing power to buy 100's of thousands if not millions of OR headsets and sell them at a discount - but are they really likely to? Being MS, surely they would have to do it - even as a special launch bundle of the Scorpio - on a mamoth scale of 100's of thousands (world wide), anything less and it would surely be seen as a drop in the ocean and potentially mis leading (at how few are available) and could backfire hugely. Even discounting by £200 a bundle would be costing them £20m / 100,000 units. Given how much MS would be losing on the console itself - is this possible? At a Guess I would suggest the Scorpio is going to start at around £350 - £400 somewhere around that (maybe including a game or two - which of course might cost them zilch)
Of course this doesnt cover any projected savings OC may make in the next 6 months and any reduction in the retail price (not to mention how quickly OC would actually be able to produce this many headsets which might be a huge challange in itself)