The leaks keep rolling in on Samsung's (OTC:SSNLF) Galaxy Alpha. If the rumors are to be believed, Samsung plans to launch the device this month -- ahead of Apple's (NASDAQ:AAPL) usual September upgrade cycle. While the product specs are still being confirmed, Samsung clearly intends this to compete with Apple's iPhone 6. Apple investors would be wise not to discount this product.

Another iPhone killer? We've heard this before
To be fair, Apple investors have heard this before: BlackBerry, HTC, Google, and Nokia, among others, have held this dubious title, and none of them knocked Apple off its perch. While many experienced success early in the smartphone revolution, more recently the market has become for all intents and purposes a duopoly.

A surprising Canaccord Genuity study seemed to confirm this. When it comes to smartphone profits, probably the best measure of dominance, the report showed that Apple and Samsung had the only profitable smartphones in the third calendar quarter of last year -- taking an astonishing 109% of all smartphone profits. All other handset vendors were left out in the cold during that period.

And as far as Samsung's new effort is concerned, it appears it brings to the table an improved, but not game-changing device. In addition to the new 4.7-inch display is a new metal-based bezel, the camera sports a 12 megapixel camera with autofocus, LED flash and a secondary 2.1 megapixel camera. As far as connectivity goes, it continues to have a differentiator from Apple with the Micro USB port and also continues to bring Wi-Fi and Bluetooth 4.0 to the device.

The problem: Apple is becoming increasingly reliant on iPhones
Compounding the urgency is Apple's increasing reliance on iPhones for revenue. If you look at Apple over the last eight quarters, you can see the company leaned on that signature product. The chart below will give you context:

Source: Apple's 10-Qs/Data Sets.

Although Apple improved in its diversification last quarter, with iPhone revenue clocking in at 52.7%, Apple reported over 50% from one product in seven of the last eight quarters. Last quarter, the reported iPhone sales percentage was nearly 650 basis points higher than the fourth fiscal quarter of 2012.

Even worse, in the high-volume quarters, which for Apple is the holiday-laden fiscal first quarter, the percentage of revenue provided from the iPhone typically jumps over 55% -- as was the case in 2013 and 2014.

In some ways, Apple fans have benefited from a higher percentage of revenue going toward the iPhone. Multiple third-party sources have stated that the iPhone is the company's highest-margin product. If so, Apple has increased its gross margins -- once a cause for Wall Street concern -- merely through favorable product mix. However, overreliance on a single product can make the investment riskier, especially in the face of U.S. smartphone saturation and possible direct competition.

Apple investors should be informed, not afraid
Although Samsung has been Apple's most worthy competitor with its Galaxy line, it doesn't seem the cell phone market is a "winner take all" proposition. Rather, it appears more suited for a comfortable duopoly at this point. In addition, besides a few upgrades, it appears the only tangible difference to Samsung's new phone is that the aforementioned size is smaller than its predecessor -- the Samsung Galaxy S5 -- that clocks in at 5.1 inches to compete with Apple's rumored 4.7-inch display.

However, as Apple's iPhone sales as a percentage of company revenue continues to hover at a high level, Apple fans should watch for any threat to the company's iPhone dominance. CEO Tim Cook has said that Apple is close to unveiling new products -- the tech giant's investors should hope he's right.