The article isn't, perhaps, as sensational as the newsclip item headline suggest, and it at least implies that the observations aren't really limited just to Amazon, but may be similar to what other ebook distributers are seeing. It refers specifically to a small(?) segment of the Amazon ebook market, although there's the suggestion that the behavior reported may extend - at least to some extent - into other parts.
Probably worth a quick read, for anyone considering submitting a book for distribution by Amazon (or Barnes? Kindle? etc), just for awareness of what can happen to your book ... maybe.
(The implied numbers are unexpected, but aren't really backed up very believably.)