Apple, which has really been to the school of hard knocks recently, is more than ever missing the magic of Steve Jobs, said Walter Isaacson, author of the best-selling biography of the late co-founder of the tech giant.
"What may be missing is the unbelievable visionary like a Steve Jobs, which you just can't say, 'Oh, let's replace Steve Jobs.' It just doesn't happen," Isaacson told CNBC's "Squawk Box" Thursday.
"Nobody can replace Steve Jobs," Isaacson argued. "He was the greatest genius in terms of just knowing intuitively the type of things that would be objects of our desire."
"Tim Cook is a great CEO. And Steve Jobs always thought he was great," Isaacson acknowledged, but added Apple is long overdue to come out with "the next big thing."
"I got the watch, but I don't use it that much. I don't think the watch is the next big thing," Isaacson said, a notion shared by many analysts and experts who follow Apple.
Every four or five years starting in 1998 when Jobs came back, Apple was able to create landmark products, Isaacson said, like: "I didn't know I needed a thousand songs in my pocket, but I can't live without this absolute thing of beauty, the iPod." He also pointed to the iPhone, the App Store and the iPad.
But Isaacson recalled that Jobs didn't count any of those products or devices as his great accomplishment. "It was the team that got put in place," including Cook, design guru Jony Ive and marketing chief Philip Schiller.
Isaacson said Cook may yet find his own way at Apple. "One of the things Steve Jobs said to Tim Cook is, 'Don't wake up every morning and say what would Steve Jobs do.' I think Tim Cook can lead the company in his own direction without trying to replicate."
Earlier this month, shares of Apple logged their longest losing streak in about 18 years. The stock, already on the decline into the tech giant's late April earnings release, nosedived after the firm delivered weaker-than-expected quarterly profit and revenue on a first-ever drop in iPhone sales. Quarterly revenue dropped year-over-year for the first time since 2003.
Cook, in a CNBC interview that aired May 2 on "Mad Money," tried to reassure concerned investors.