Whine here - this version used to be available on Kindle - I know, because I purchased it. However, it is no longer available and my copy got ‘updated’ to just the regular text, sometime between my original purchase in 08 and ~2015.
I now no longer solely purchase Kindle versions of books that have some characteristic I value, and I think Vinge would solidly approve of that stance. Not sure about the reaction of the Blight, though.
In the pre-Kindle days, Amazon sold it as an Adobe DRMed PDF, which is how I bought it in 2006. When they introduced the Kindle they retired the Adobe DRM servers, and since they did not alert me as to this happening (despite the ebook being registered to an email address), my copy turned into a pumpkin.
It took me a few back-and-forths with Amazon's customer support to get them to even acknowledge that this had happened. Most of the reps I communicated with weren't even aware that Amazon had sold ebooks before the Kindle. They wanted to just give me the Kindle version of the regular eBook, but grudgingly gave me a refund instead, because I insisted on either the full annotated version in any form or a refund (I already own two copies of the regular book in paper form).
Another possibility is not to keep the books just in the Kindle/Kindle app and to regularly download them to your computer and back them up. The DRM can be stripped too.
I now no longer solely purchase Kindle versions of books that have some characteristic I value, and I think Vinge would solidly approve of that stance. Not sure about the reaction of the Blight, though.