ps. if its linear, then 30 secs for a 500 page novel would mean 300 secs ( 5 minutes) for a ~5000 page omnibus or a
war and peace. which is why I asserted minutes not seconds a few posts back.
I think the Libby app from overdrive - for library books - does a recompute on the fly of pages, but typically that's running on an android device with more cpu power than an e-ink reader
I agree that amazon
could do pages left in chapter quite easily, as a chapter will have been pre-loaded into ROM
whether they
should do it is a different debate. it would maybe be interesting to check if there's any demand for it in amazon's own forums
and there is the odd annoying author who does not believe in chapters, so the book comes as one long scroll. e.g. Wilbur Smith , in some of his books; Cormac McArthy, who does not believe in punctuation either

; Jack Kerouac, ( pre being "remastered" for modern readers... )