If you want to build your own software you must build your own Hardware. Steve Jobs.

In 1970s, all computer companies (Apple, IBM, HP.. ) used to build both software and hardware as one unit, all of them had same problem with personal computers; the need for a great software with amazing user interface and affordable price but the problem exist.. Hardware is super expensive.

Steve Jobs left apple in 1985, while it was losing money and followed him 4 CEOs whom failed to make it better.

Jobs started a computers company called NeXT which was building both software and hardware and selling them as one unit, Although the company didn't make much money but it widely became famous in the 1990s.

During 1990s, computer companies started to focus on either Software or Hardware, this was somehow the correct decision as specialization is a key to success.. beside many companies were challenged in building a hardware that supports different software by building an adaptable middle-ware that work as wrapper between hardware and user interface software or what can be called Operating System - AKA OS.

Apple keeping itself focused on both software & hardware kept on losing money with it's great hardware and poorly software with the rise of Microsoft Windows as one of the greatest operating systems of the decade - which copied many user interface components from Apple's earlier OS- and the growth of NeXT Pixar OS - (Yes Pixar the company making super animated movies now days) run by Jobs.

1997 Apple bought NeXT operating system and Steve Jobs became Apple computers CEO once more, starting the Macintosh project again with new OS based on NeXT's and Apple's super hardware.

Although all computer companies building home computers (AKA Personal Computers and Laptops) focused on either software or hardware, Apple kept on developing both and making a complete personal computer.

More computer platforms started to rise up with Music players, Mobile phones and tablet, Apple kept in the lead because they kept on building every component of their product.. almost every component.

Many alliances has been there between software and hardware companies, none has lasted long enough.. and now days most of software companies are following into Apple's steps by either purchasing a hardware company or merging with it in specific product(s).
Google is building it's own hardware for mobiles (Nexus) instead of depending on Samsung.
Microsoft acquiring Nokia for smart phones.

Bottom line, Apple is awesome and it offers not the cheapest but the highest quality technology regarding everything, why? read the above again.