>>285826350
>Better tracking & no occlusion issues
>Less screen door effect, higher detail, etc
>Significantly higher refresh rate (don't forget Rift S is 80Hz)
>A more efficient upgrade path for tranny trackers (if that's your thing)
That's enough to justify an upgrade for me, but then again I'm not a poorfag. 

>a new headset is probably already on the market
If any company was stockpiling headsets ready for release, Corona would have slowed them down enough. I especially doubt there would be enough supply for, say, a September/ October launch. There've been no announcements or leaks for any other headsets other than the HP one from last week either so it's unlikely.