I agree with bgroovy. Prior to Sony's 'moar speed' publicity, we all thought any SSD would do as it's such a huge improvement and only considered costs and capacity, not speed, when discussing them. Why would any console company going from 5.25" laptop HDDs to several GB/s low seek-rate SSD feel it wasn't fast enough? If MS and Sony had both gone with a cost-effect 20x speed-up, none of us would bat an eye-lid. It only sounds 'weak' because Sony has decided to prioritise it. Unless the fanboys turn frickin' load-times into next-gen's 'flops', it shouldn't be an issue of contention. A choice between 2 TB NVMe 2 versus 1 TB NVMe 4, hypothetically speaking, may see the larger, slower option picked, with good reason and without that being a dumb move. Of course if NVMe 4 is faster and cheaper and MS went with NVMe 2, that would be a dumb move.
We should just look at MS's options in terms of costs and benefits to hit on the best long-term value, as that's most likely the choice they'll go with. What's the price difference between the latest and older techs?
SSD is not only load time but streaming too.