Apple (NASDAQ:AAPL) closed out Friday at $547 per share -- 22.4% below the all-time highs the company set in September. The iPhone 5 launch broke records as expected but failed to light a fire under the stock. The iPad Mini didn't help much, either.

We're looking at the end of an era, folks. The mere mention of a new Apple gadget is no longer enough to spark a stock market feeding frenzy. Investors are looking for the steak behind the marketing sizzle, and Apple doesn't deliver.

The company has been a turbocharged sports car for the better part of a decade. Starting with the original pastel-hued iMacs and first-generation iPods, Steve Jobs took Apple from the brink of bankruptcy and created the world's most valuable company. Investors have been rewarded with a ridiculously awesome 6,800% return over 10 years. I totally understand if you fell in love with the stock and expect the joyride to go on forever.

It's the end of the ride as we know it
But nothing lasts forever. It's time to shift gears. The massive growth phase is over, and Apple will become more of a steady banger from now on. You know, the wood-trimmed station wagon or eight-seat SUV that takes you where you need to go but you don't want your friends to see it. Time to trade in the old Corvette.

Under Jobs, Apple ran on imagination and nitroglycerin. The Apple ecosystem, masterfully designed around the iTunes store, pulled you in and kept you forever. If you joined the Apple faithful in the past 10 years, chances are you'll never buy a Microsoft (NASDAQ:MSFT) Windows PC again, nor consider any smartphone not named "iPhone." This is why Apple will never die in a ditch like so many former giants of the volatile computing sector. Once the company sinks its hooks into you, there's no way back.

But new recruits are getting harder to come by. The iPhone 5 and iPad Mini are surely the finest versions available in Apple's phone and tablet lines; you'd hardly expect to see the products getting worse year by year. But they're not the revolutionary mind-benders that Steve Jobs used to present all the time. Instead, they're incremental refinements on what came before -- nice enough to inspire a few upgrade trade-ins, but not blowing your hair back with total awesomeness.

New CEO Tim Cook is not a visionary genius. He's undeniably a master of efficient operations. He practically sneezes sales data and supply-chain numbers. From Jobs, you got confetti and rainbows. That's how Apple was designed to work, and Cook isn't up to the task.

It's starting to show. Both customers and investors are catching on.

Nothing compares 2 U!
Fellow Fool Evan Niu likes to point out that no other tech giant can deliver the unique blend of high sales growth, fat profit margins, and the low price-to-earnings valuation that Apple sports. Intel (NASDAQ:INTC) is cheap but not that profitable. Google (NASDAQ:GOOGL) is a fine grower, but the stock is relatively expensive. Microsoft just falls short on every count.

But you know the old adage: "Past performance is no guarantee of future results."

Apple can look back at a tremendous decade of insane growth, and the rocket engines are still firing. Chances are, the next quarter will look great, too -- Apple's mojo should vault it into another fine holiday season. But Cupertino cannot afford to rest on its laurels for too long, lest the trendsetters and taste-makers turn to Android, or Windows Phone, or maybe even Research In Motion's (NYSE:BB) upcoming BlackBerry 10 when they get bored with the same old iPhone presentation. Looking at this year's new products, it looks like Cook is getting awfully comfy on his enormous laurel pile.

Yes, there's value in presenting a consistent user experience. Apple sure delivers that. But there's a fine line between consistency and complacency, and I think the company falls on the wrong side of that line. The iPhone hasn't changed all that much since the very first version, save for cosmetic design improvements and the inevitable evolution of faster and better hardware. Moreover, every new product Apple presents nowadays appears to be another spin on the basic iPhone or iPod Touch platform.

The wow factor is fading fast. Next year, the runaway sales growth may very well flatline or even turn negative. And without that growth promise, Apple becomes just another stodgy mastodon, defending an old business model rather than inventing the future.

But hey, Apple will at least find some old friends around here. Microsoft has been in that zone for 10 years, for example. Nobody buys Microsoft stock with triples or five-baggers in mind -- they buy it for solid but unexciting performance and expect the dividend to rise.

Yep, Apple already bought that station wagon. Time to fill 'er up and get on the road.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.