A few comments on an electronic version of B&GR. Which, by the way, I'd love to see.
..if a publisher adopted that strategy nothing would ever go out of print, ever...
Ideally, that's the case. In reality, the experience with digital music sales indicates that publishers will, for various reasons, take electronic product in and out of print, even though it costs them nothing to keep the product available.
...the Kindle format's search / lookup / contents / indexes & general navigational aspects, in its current form, are not ideal for using with a reference books...
Technology and products are always changing. But if you're a user who wants that sort of function, you'd be better served at the moment by the Barnes & Noble eReader software. I've used the Nook color for a year now and have been quite satisfied with the search, highlighting, bookmarking, index/contents, etc. (Full disclosure: my wife works for B&N, but has nothing to do with either the Nook or their eReader software.)