I am just a single data point but still I have a story to tell: I had a B&N Nook. Then I didn't and I still was buying Nook eBooks. You know why? Because DRM was a fig leaf. They had their DRM solution which was so easy to strip it's not even funny -- they encrypted your books with a key based on your name and credit card number (this might've originated with ereader.com). Then in 2015 March they changed algorithms and it was not so easy any more and I walked.