Have you never used a digital library to check out an e-book? They use DRM. And even then, libraries have a different rights model, involving the fact that the

Have you never used a digital library to check out an e-book? They use DRM. And even then, libraries have a different rights model, involving the fact that they legally own each copy they lend out as a distinct purchase of an IP license, placing a distribution concurrency limit on each work of “however many copies they’ve purchased”. They aren’t legally allowed to just make more copies to serve more users; they have to buy those additional copies. And yes, this applies to both physical books and e-books lent out by libraries. (It also applied to the DVDs Netflix used to be about loaning out.)