 By then, the excitement slowly died. Not the Kindle, just the hype. But over the past two years, the Kindle has been quietly making a comeback. Why? Rediscovered by Gen Zers on TikTok. Kindle sales grow each year by double-digit percentages. Now, after all is said and done, though, print books are still the most popular. But with e-books, digital book borrowing is hot. In almost forgotten public libraries, more than 370 million e-books were downloaded last year alone.