I'm hoping they surprise us with a Spring 2020 release + full backward compatability day one
I'm sure that there will be full backwards compatibility with Xbox One, but I would be surprised by a spring 2020 release.
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I really doubt you'll be seeing exclusive games for either console for a couple years. I feel like both MS and Sony are going to want to keep things cross gen for as long as possible.
I'm going to copy/paste what I said in another thread haha —
I honestly thought it was pretty obvious this past year or so that Xbox games during the early 2020s will more than likely be on both the Xbox One family and Xbox Scarlett family with scaling between all. Microsoft's current compatibility strategy (on top of the fact that Halo Infinite still hasn't been shown yet) would pretty much fit with this.
The upcoming consoles having compatibility with the previous gen will make cross gen titles during the early life of the new consoles a no brainer. You're literally missing out on money and users for the sake of pretty pointless exclusivity — especially in this era of crossplay.
I'm sure that the majority of Next Xbox and PS5 games during the first two years of both systems lives will be third party. I'm also positive that Sony will still sell slim PS4s and that Microsoft will still sell Xbox One S models. Both will be cheap by that point. The Next Xbox and the PS5 will be backwards compatible too obviously. Therefore, the early libraries of the PS5 & Next Xbox will more than likely be bogged down a bit from 2013 model/spec PS4 & Xbox One support. I don't think this will hurt the sales of the PS5 and Next Xbox in any major way though. "Next gen hype" should still be large. For example, the visual improvement of multiplats like NBA 2K, FIFA, and Destiny alongside their great marketing helped the launches of PS4 & Xbox One far more than their early true exclusive games.
I never see the PC gamers that I know that play at ultra settings complain about PC gamers that play at far lower settings and how it "holds them back". I think things will honestly be fine. You'll get some complainers due to them being used to previous typical game console transitions, but I think they'll be a very small group.