It's quite possible that sometime in the future, even the near future, an ebook library on a given subject will be the equal of a paper library on that same subject. Right now that is not the case for a significant number of domains, just because some of the important books in those domains are not yet available as electronic books.

Of course, if you regard books as fungible, this might not matter to you. For some of us, it is important to have a particular book, not just a substitute. For instance, if I want clarification in calculus, I want to refer to the particular calculus textbook I have spent a lot of time studying, not to a different text. If I read 20,000 leagues under the sea, I want to read one of the recent and competent translations to English, not one of the earlier ones that had mistaken conversions from metric to imperial and entire passages left out because they offended the translator. As far as I can tell, none of the Kindle nor Gutenberg versions of this book are one of the good translations. Similarly for Gibbon's Decline and Fall of the Roman Empire: I want the Womersley edition, and that edition isn't currently available in an electronic format. If I'm discussing history with someone I might want to cite a passage out of one of the books I've read on the subject, a particular book, like The Rise and Fall of the Third Reich or From Dawn to Decadence. Neither of those are available as electronic books. Though I guess if I never read anything but electronic books, this would not be a problem: I wouldn't want to cite them because I wouldn't have read them.

Many books I care about probably will never be converted to ebooks. They aren't old enough to be classics, but not recent enough for the publishers to feel there would be a profit in reissuing them in a new format.

And of course there is the problem of DRM. There is then the possibility that a book you thought you owned has turned into a pumpkin because because the ebook reader refuses to show it to you unless it can talk with a license server that no longer exists, because the vendor you bought the book from has switched formats. This happened to me a few years ago with an Adobe eBook I purchased from Amazon: they dropped support (or Adobe dropped them, I'm not sure) when they switched to Kindle. The fact that the transition between possessing a working electronic book and possessing a non-working electronic book can happen silently; the only way you can be sure is to regularly open up the book and to test it every time you move to a new computer or even reinstall the operating system. This does not contribute to a feeling of confidence. Until the books I care about are available in some confidence-inspiring electronic format, I will retain my paper library, despite the inconvenience of storing and moving it. The inconveniences minor compared to the benefits I derive from it. I'm not sure whether one of these benefits might be signalling to the world how smart I am; nobody has ever commented on the matter in a positive way, thought a few acquaintances have expressed opinions similar to yours.

On the other hand, if all of the books you care about actually are available as eBooks and you have some confidence that the the ones you care about retaining will continue to be available (not turn into pumpkins), or if you regard reading as a simple pastime where you don't much care which book you read next and are willing to choose from those available in electronic form, then eBooks, as they currently stand, are great. They aren't for everyone though. Not yet.