I can agree with this. I have one of the first thousand or so Kindles that were sold. I love and I use it every day. And so far I have bought a little over 500 titles for it so far. And in the last two years I have gone to E-Books exclusively. It just makes sense for me to have my entire library in one hand.
I also have around 60 file boxes of books down on the garage that I am working on selling or donating. As a Kindle version of one of those titles comes available I buy it. With many of the titles in storage going back to the 40’s and 50’s that is going to take some time. Of course I just bought a Lester Del Rey collection for 99cents as a E-Book. What a deal!
And of course as always there are some exceptions to that rule. Any Survival/Prepping type of book is also bought in hard cover. If TSHTF then electricity to charge the Kindle may be hard to come by.
That is the reason why I got my Kindle. I was simply running out of room for all the books. I have really enjoyed mine. I like the ability to search for a new book late in the evening when the book stores are closed. Also the cost of the book is 1/3 of a hardback, so for me that is 3 times as many books.