Credit: Kaitlyn Cimino / Android AuthorityI wouldn’t be exaggerating if I said Amazon’s Kindle lineup has been fundamental to the e-reader category taking off. While there are many more alternatives now, in a variety of convenient sizes, Kindle still remains the default choice for many people. While familiarity is one reason, the other is the interface designed around your ebook library. However, with a slew of recent changes, Amazon appears to be pushing away readers, including some of the oldest backers.Last year, Amazon strengthened its hold on ebooks, leading many users to jailbreak their Kindle readers. More recently, it announced plans to remotely kill Kindle devices sold until 2012. Effective May 20, older Kindles will lose access to the online bookstore, and users won’t be able to read anything other than the books already downloaded to their devices.