Just because you don't invite people over to your place doesn't meant that I don't. In fact, I do, regularly.
Also, if you put the pieces together, the fact that you have a device around that you're comfortable reading on most of the time doesn't mean that I do. My phone is a terrible device for reading on (as is my laptop, honestly), and the only one that I have around as often as I have a book in my bag.
Giving someone a book has an emotional connotation that loaning someone something on an electronic service does not. That may change in future generations, but for me, and my ilk (most of whom also don't read books on electronic devices), giving someone a physical book means far more than loaning them something with an internet service.
I have no problem that in your social environment that Kindle books are superior to physical books. But you said that you can't understand why anyone else would prefer physical books, and it seems the simple explanation is that, well, everyone isn't you.
I'm not trying to sell anyone on it, I'm more interested in seeing if people switch back after they've tried it. That would be more interesting to me.
You still have all the same benefits you mentioned above, minus the ability to turn off distractions:
• You don't need to own an ebook reader or tablet. Amazon's Kindle App is free and works on practically anything: Mac, PC, iPhone, even a Chrome plugin if you don't like having a desktop app.
• You keep a physical collection in your reader just as you do a bookcase. It's not the exact same thing, but that's something I noticed recently: hardly anyone visits me at my apartment, but I am often going to meet people at cafes and with me I bring my laptop or phone, and on those I have my entire collection of books.
• You can loan a Kindle book to a friend on Amazon, and it's free.
• You can read on any device, and you almost always will have your cell phone with you. I usually do most of my reading on the BART or CalTrain, or waiting in lines.
• You don't need to carry a bag or remember any books, if you have a digital collection they're always with any of your devices. If your device is stolen, you still have your digital book collection.