Even ignoring the fact that physical books last for much longer than a decade, the alternative to DRM'd books isn't physical books. It's digital, non-DRM'd books. And the lifetime of a DRM-free digital copy of a book is practically infinite.
This is only really true for books published during a certain interval when high acid (wood pulp) paper was common. Before the late 1800s paper was typically made of other plant fibers ("rag"); by the mid-late 1900s de-acidified wood pulp paper was cheap enough to be common. Many books today still have a small remark in the front matter telling you that it was printed on low-acid paper and will last.
Pulp paper was much cheaper, which is how lurid mass-entertainment paperbacks came to (a) exist at all and (b) be called "pulp fiction".
I think you're being downvoted too much for this. It's a reasonable statement, and it's the premise of the licensing mechanisms libraries pay for with ebook subscriptions. Books have an average shelf life, you can compute the number of reads per copy and use that as a proxy for how much to charge a library to lend an ebook. (That's the premise anyways, there's plenty of politics to deal with too)