Bill Gates spoke of this context-aware OS at a lecture in the mid-00s. He specifically called out future phones (this was pre-iPhone era) that would have location context (work/home/mobile) and load secure, sandboxed datastores and profiles depending on that context. He also spoke at length about how desktop computers would transform into accelerators, like your gaming GPU at home or your additional processors and memory at your workstation. It was a grand vision of ultimate portability, with clear lines between work and personal lives enabled through technology.
Then he showed off the Fossil MSN watch, and suggested future iterations may do away with phones entirely and act as methods of identification for digital systems.
And then, like all things Microsoft, they abandoned the concepts entirely. Apple and Google cribbed most of the ideas for themselves in some form or another and saw wild success with them, though to date nobody major has really attempted to create that mobile vision Gates spoke of - other than Maru, and for a time, Google on Android.
It’s a shame, really. I like the idea of validating my public key via NFC from my Apple Watch to login to work machines or my home boxes (a la SSH). Seems like it’d be easier to wrangle in the long run, especially with job hopping being the norm.