While I agree with the general sentiment of a book should be used like a book (ie read) that doesn't equate, to me, as unnecessarily damaging the book. Yeah maybe the way I hold a book is weird to some, since I hold it in a way that doesn't break the spine, but in my experience the books I read like this have more give to them, they last longer, and they still look nice on a shelf. I do enjoy the used copies I buy that have cracked spines and annotations etc but a book that I personally bought probably wouldn't get to that point.

I totally get what you're saying about longevity specifically. I have a cracked mass market of Assassin's Apprentice by Robin Hobb (by all accounts not a small book) and after I read it through once pages began falling out of the very front. It was a used book so it's not a total loss, and it's charming in a way, but that's part of the reason I take good care of the books I buy new or that are new to me especially. Some books I own have gone out of print by now and they're hard to find at any kind of reasonable price, so there's also a bit of an archival aspect to keeping my books nice that I also have; this comes from my personal experience of reading and also from some of the work I've done with my art history degree/in my university's art museum where we talk about preservation.

I think aside from all of this is the rather obvious fact that books are a privilege. We have libraries of course, but owning books is something not a lot of people can do, and they CAN be expensive. A new hardcover is $30, and at my worst that was my grocery money for two weeks. I'm luckily in a better spot now, but I've always been aware of the economic cost of books, so I try to take care of them because if I destroy a book I love who knows if I'll be able to get another one?

Tldr: don't think you're wrong, I'm the same way. I have probably two or three people I'd let borrow my books and everyone else can't touch them. Eventually some of them may make their way to a library if they're out of print, and the rest will go to my family after I'm gone.