In an interview segment on Monday, tech pundit Henry Blodget stated that he is planning to sell his Apple (NASDAQ:AAPL) stock soon. While Blodget believes that Apple will report stellar earnings for the first quarter of its 2015 fiscal year and strong guidance for the current quarter, he is worried that growth will evaporate thereafter.

It's true that growth may decelerate in the second half of this year. However, I'm in no rush to sell my Apple shares. The company trades at a very modest earnings multiple, sits on a massive cash pile, and still has a few key growth levers at its disposal.

The last iPhone upgrade?

The new iPhones are a big hit -- but plenty of iPhone users have yet to upgrade. Photo: Apple

For Blodget, one of his biggest concerns is that the iPhone 6 and iPhone 6 Plus are the ultimate iPhone upgrades -- once people get them, they will see no need to upgrade again.

Even if this were true, 75% of iPhone usage comes from older phones. This suggests that there are still 250 million to 300 million upgrades waiting to happen.

It's also way too early to assume that this will be the last major iPhone upgrade. Aside from obvious small improvements that Apple could make -- to the camera, processor, or RAM -- there is always the potential for more innovative changes.

For example, Apple could greatly improve battery life; introduce curved, flexible, or 3D screen technology; remove the home button and move Touch ID to the back of future models to shrink the device without sacrificing screen size; and other potential changes that nobody has even thought of yet!

Additionally, the iPhone user base is still growing. Apple is just reaching supply-demand equilibrium for the new iPhones now, which means that (to some extent) upgrade sales to loyal iPhone fans have been crowding out sales to new users. In China, 4G phone service is just taking off, and Apple is well positioned to capitalize on this shift as the iPhone serves as a status symbol.

Could the much-maligned iPhone 5c be the next big iPhone growth driver? Photo: Apple

Lastly, Apple could use the iPhone 5c to attack the mid-range market in developing countries. Apple could sell the iPhone 5c for approximately $350 in countries like China, India, and Indonesia while enjoying a tidy profit. This would negatively impact its average selling price, but it probably would not cannibalize highly profitable sales of the larger models.

Growth outside of iPhone
Another important consideration is that while Apple has relied heavily on the iPhone for revenue growth in recent years, that might be less true going forward. First, the Apple Watch represents an entirely new product category.

Even if Apple Watch skeptics (like Blodget) are right that the gadget will fail to win widespread appeal, Apple could sell tens of millions in the next year just getting 5% to 10% of iPhone users to buy one. That could add $10 billion to the top line, which represents significant growth considering Apple has grown revenue by an average of just $13 billion annually for the past two years.

Greater penetration of the iPad in businesses across the world -- potentially helped by the release of a 12" to 13" model -- could drive a return to iPad sales growth. Meanwhile, the massive Apple user base will keep high-margin App Store sales rising rapidly.

Plenty of reasons to stay bullish
At some point, Apple stock could rise to a level where I would sell all of my shares. However, the stock currently trades for less than 15 times FY15 earnings estimates -- and rather conservative estimates at that. At that level, Apple stock still looks fairly cheap compared to the rest of the market.

Apple also has more than $100 billion of net cash on its balance sheet. This will allow it to take advantage of any potential dip in the stock price to buy back even more stock, thereby boosting long-term EPS growth.

The company has plenty of levers to keep iPhone sales growing beyond 2015. It is also poised to get a larger growth contribution from its other business segments thanks to the launch of the Apple Watch, a potential turnaround in iPad sales, and continued App Store sales growth. These factors provide ample reason for investors to continue holding their Apple shares.