That’s the question of the day for Apple followers as the company’s fans on Wall Street lick their wounds from last night’s disappointing earnings report. The stock fell 12.4% today to $450.50. That’s the company’s worst one-day performance in about four years, and puts Apple shares right where they were about year ago. The company’s market value of $423B is still impressive, but a far cry from late September around the time it released the iPhone 5. Back then, investors thought it was worth more than $659B. To put this into perspective, the drop in the perceived value of Apple over the last four months amounts to more than the value of Comcast, Disney, and Viacom combined.

The most popular explanation for Wall Street’s souring view of Apple is that investors are disappointed with iPhone sales — even though the company sold a record 47.7M in the last three months of 2012. That was short of expectations, and it follows recent reports that Apple is cutting back on orders. The fear is that Android phones are catching up in features and overall coolness, just as Microsoft’s Windows 8 phones begin to make headway with some fans and Research in Motion prepares its bold revamp for its Blackberry phones. There’s also a lot of demand for handsets with screens that are larger than the iPhone’s. Meanwhile, Apple’s iPads face tough competition from Amazon’s Kindle Fire and other Android-powered models. While Apple boasts about its products’ features, rivals “are using price as a lever to get traction in the market,” says BGC Financial’s Colin Gillis.

No wonder Apple fans are so eager for it to introduce another revolutionary product — possibly the much-discussed TV that would make it far easier for viewers to find and handle conventional programming and Web content. CEO Tim Cook told analysts yesterday to stay tuned, observing that it’s a topic of “intense interest for us” and that “there’s a lot we can contribute in this space.” If he can, then Apple’s stock will look like a bargain. If he can’t, then look out. Apple still has a long way to fall.