On this day one year ago, the digital world was shaken to the core when Apple CEO and tech visionary Steve Jobs passed away. And amidst all the mourning, there was one lingering question on people's minds: what's going to happen to Apple without Jobs at the helm?

One year later, it seems Apple is stronger than ever. The new iPad, as well as the release of the iPhone 5, have boosted Apple's sales exponentially. It's definitely been a banner year for Apple, but how long can it last? According to some, the tech giant is already starting to show some signs of struggle without the leadership of Jobs.

The forceful visionary — considered one of the greatest business and marketing geniuses ever — set such impossibly high expectations at the company that with each passing day, maintaining Jobs' standard becomes more difficult, Apple watchers contend. Jobs' name is synonymous with the Apple brand not only in terms of innovation but in culture: He was its public face, as Walt Disney was with his company, says Paul Saffo, a technology futurist who teaches at Stanford University.

"Apple just had one of the most extraordinary 15-year runs" in business history, says Adam Lashinsky, a Fortune writer and author of Inside Apple. "It is unreasonable to duplicate that, even if Jobs were still alive."

To be sure, there have been occasional misses. The flawed new map application on iPhone 5 in all likelihood would not have passed muster with the perfectionist Jobs. Apple CEO Tim Cook said he was "extremely sorry." A TV ad judged as subpar aired during the London Olympics and soon disappeared. The humorless and cheesy "Genius" spot never would have made it past the drawing-board stage with Jobs in charge, former Apple employees say. (Jobs had his own missteps, including antennagate, when the signal strength of the iPhone 4 was diminished when users touched the lower left edge of the phone.)

"I shudder to think what he (Jobs) would have said about that ad," says Tom Suiter, whom Jobs hired as a creative director in 1982 and who recently helped design J.C. Penney's new logo. "The bar is so high for them now." The hands-on Jobs micromanaged day-to-day operations, down to helping design and conceptualize TV ads.

Apple is still on top, for now. And I predict it will remain on top for at least the next few years. After all, the company has developed a fiercely loyal fanbase (or cult as some people put it...) that will continue to purchase Apple products no matter what they are or how much has been changed. But the one thing that I think kept Apple on the top was the innovation of Steve Jobs' devices.

When the iPad and iPhone first came out, there was nothing like it on the market. But if Apple just keeps on re-releasing products that have already been on the market, and in some cases improved upon by their competitors, then eventually the company will just go stale. I'd love to see Apple come up with some brand-new, never-before-seen type of wonder device again. But without the innovation of Jobs, it's hard to imagine how Apple could top themselves like they've become famous for doing.