SAN FRANCISCO — Books are dead. Long live the book.

Even as the universe of printed matter continues to shrivel, the book — or at least some of its best-known features — is showing remarkable staying power online. The idea is apparently embedded so deeply in the collective unconsciousness that no one can bear to leave it behind.

Amazon brags that on its latest e-reader, “the pages are virtually indistinguishable from a physical book.” It recently introduced the Page Flip feature, which mimics the act of skimming. Bookshelves in living rooms may be becoming a thing of the past, but order an e-book from iBooks and Apple promises it “downloads to your bookshelf” immediately.

Some functions of physical books that seem to have no digital place are nevertheless being retained. An author’s autograph on a cherished title looked as if it would become a relic. But Apple just applied for a patent to embed autographs in electronic titles. Publishers still commission covers for e-books even though their function — to catch the roving eye in a crowded store — no longer exists.

What makes all this activity particularly striking is what is not happening. Some features may be getting a second life online, but efforts to reimagine the core experience of the book have stumbled. Dozens of publishing start-ups tried harnessing social reading apps or multimedia, but few caught on.