I was looking into this device since I like the idea of digital paper and because it runs Linux but between the supposedly meh reading software, the tiny (8GB) storage, the very expensive accessories and now this move I'm soured on it.

Will be looking into the Boox Note Air instead.

Ugh. I own two remarkable tablets (version 1 and 2), and I use them a lot and really like them but I just don’t want another subscription.

Is there a good open source alternative?

Check the terms - if you already own them, you're grandfathered into the Connect (highest tier) package for free (for now, at any rate).

I recently got a second hand remarkable, and absolutely love it, but not sure how I feel about them pulling this sneaky (however justified it may be). It's not that my assets are in jeopardy, but I'm slowly developing a whole new workflow, which I don't want upended 12 months from now if they decide to charge everyone...