the cheapest MacBook Pro from last year already has faster write times
https://9to5mac.com/2016/11/01/the-late-2016-entry-level-13-macbook-pro-has-a-ridiculously-fast-ssd/
But that is not the point; solid state memory will be integral to the next generation. Otherwise we would be looking at several minutes of loading time before a multiplayer match could start. Current SSDs use old technology, 3D memory will get into high production later this year, this will drive prices down significantly.
Also keep in mind, at the end of 2019, the fastest solid state discs will write at 10.000MB a second, 5.000 would be seen as a budget model
I'd say my specs are more realistic than the general consensus on what Scorpio would be.
But anyway, that was my guess. I am happy to see new views now that Scorpio is out, on what Xbox One 3 should be