When you thing of portable device that changed the world, it a phone. Having the phone matters a lot, how much can apple or huawei do with their own hw or OS, they are flexible and got way wider fan base.
OS is the easy thing, having tool to bypass some apps from existing OSes also helps a lot, not to mention apps for windows are plenty, web page apps aside.
Besides that, most important factor in mobile device are cameras, no matter the price or OS, if the cameras are poor, there will be not enough enthusiasts. Trend now are 200mp ones, not 12mp, so better not to make a mistake.
With a foldables here, there is also no limit to design, which many miss with just copying each other.
Folds also works better for Microsoft as it is basically folded tablet, not much of a change(maybe just those cameras).
We went from container to desktop, to laptop and tablets. If the Microsoft miss the folded opportunity right now with fold type device vacuum in the market, it may be hard to do later.
I really miss also band devices, as if it got nothing with productivity... recently got to see some gamers pills, like for good night sleep. It goes all together, caring about customers...