[dredmorbius]

We're already there.

The reMarkable (by reports) and Onyx BOOX (by direct experience) both satisfy this requirement.

I picked up the BOOX as an e-book reader, not a note-taking device. It turns out that the note-taking functionality is really, really good.

I still have the objection that notes are stuck in an application-specific interface. Though on balance that's not all bad.

There's also the inherent privacy risk of having an electronic rather than physical record.