Here's the rundown of the business strategy Apple is using.
The overall goal is quite simple: Reach as many markets as you can and sell good products to those markets.
Market 1 - Consumer / Entry
This is the biggest market of the 3 main markets that exist today. The demands of this market are somewhat demanding: cheap, good looking computer that can handle daily activities. Apple has tapped this market with a variety of Macs. Most are overpriced by Windows PC standards, but considering Apple's quality and warranty the price has been proven to be worth it. This is the market with the most products. Mac Mini, MacBook Air (both 11" and 13"), MacBook Pro 13" and low-end iMacs. Not too underpowered, but still weak for heavy duty work.
The Mac Mini is the entry-level desktop Mac. Designed to suit converters, it allows for the freedom of choosing your own peripherals such as keyboard, monitor and mouse. Although this is the cheapest Mac, it is arguably far from the weakest.
The MacBook Air incorporates a weak CPU and lack of a dedicated GPU in conjunction with a fast SSD to create the illusion that the machine itself is very powerful. This illusion of speed is most associated with power in the consumer market. Also, with its long battery life and portability, the MacBook Air is perfect for any average user.
The MacBook Pro 13" is Apple's consumer-level power laptop. It has the most horsepower of the consumer Mac laptops listed here. It is also upgradeable; this is a major selling point for many people. Also includes an ODD for the consumer market, because many people still use services like Redbox.
The low-end iMac is the weaker, less customizable iMac. It has the guts of most average desktops available today, but has the monitor packaged in to create a hassle-free environment that consumers love.
Market 2 - Prosumer
The new and developing market of prosumers have the most demanding needs, even more than the professional market. They want great performance and looks in a not-too-expensive package. The 13" MacBook Air, 13" and 15" MacBook Pro, High-end iMac and the Mac Mini Server satisfy this category.
The MacBook Air, as previously mentioned, is more portability-minded than performance. However, power users who prefer cheap SSDs, higher resolution screen, and the wow factor of the 13" MacBook Air are very much attracted to this laptop.
The 13" MacBook Pro is more upgradeability-minded. Prosumers looking to improve their laptops using 3rd party components but don't want to spend too much money are satisfied by this option.
The 15" MacBook Pro hits the sweet spot for prosumers. Not too big, but extremely powerful. Almost everything can be upgraded and set to match their exact wants and needs through the BTO option and 3rd party components. The laptop just screams quality and indeed is worthy of the moniker "Pro."
The high-end iMacs offer a spec bump from an i5 quad-core to an i7 for the 21" and the much revered i7-2600 as a BTO option for the 27". Packaged with the ability to use up to 16GB of RAM, this satisfies the performance needs of a prosumer seeking a desktop Mac.
The Mac Mini Server offers dual hard drives and a quad-core laptop processor. Which means while the Mac is diminutively small, the Mac Mini can offer an even more versatile setup than an iMac. The 2 hard drives can be set up in RAID arrays, the quad-core can be used for heavy computing, and the computer can be used as a low-footprint server that it was intended to be used as.
Market 3 - Professional
This is where cost does not matter. Performance is all the customer wants. Looks are only a bonus; functionality is what matters. Form factors can be ignored for the sheer power that these computers offer.
The Macs that satisfy this category are the 15" and 17" MacBook Pro, Mac Pro (all versions), and the high-end iMac 27".
The 15" and 17" MacBook Pros both offer the GPU that the 13" lacks. Both are amazingly powerful, and the 17" even offers an ExpressCard/34 slot for the professionals who might need it. Professionals also hate change; they love legacy things (see Final Cut Pro X). All of the ports and inputs that you might call legacy (Ethernet and ODD being prime examples) are there because a professional user might need them someday. The looks of the laptop are a great bonus to go along.
The iMac 27" High-end satisfies professionals that might not be able to pony up for a full-on Mac Pro while offering a great deal of horsepower.
Then the 800 pound gorilla in the room: Mac Pro. Dual CPU, liquid cooling. 'Nuff said.
See how diverse Apple's reach is? This is what lets Apple generate so much revenue. Here's some examples of effects getting rid of or merging product lines will do:
Merging MacBook Air and MacBook Pro, possibly into a single MacBook line will necessitate the dropping of a GPU and the powerful CPU that prosumers and professionals really dig about the 15" and 17". That's 2 entire markets gone. While this merge may greatly satisfy consumers, the losses would simply be too great for this shift to be logical.
Dropping Mac Pro: This would officially mark Apple's departure from professionals, servers and corporations, having dropped the Xserve which preceded it. There's many, MANY professionals who really need the horsepower of the Mac Pro. These professionals (more often companies) are the ones who buy in bulk. For example, an animation studio such as Pixar, which obviously needs the superior horsepower of the Mac Pro, might buy them in bulk. Not to mention the extreme power enthusiasts who always strive for better performance. If this drop occurs, then about 90% of the professional market will disappear from Apple's earnings. That's quite a sizable chunk, because of the sheer price of these machines.
Apple will not move in that direction. At least not now. All of the products have separate, non-overlapping and profitable markets. The reason why Xserve was dropped was lack of profits, and for the MacBook, an inefficient overlap in market with the cheaper MacBook Air.
Please, MacRumors, don't create useless speculation that a product will be dropped.
