Posted 22 February 2009 - 03:53 PM
Actually, I'm not sure what your definition of monopoly is but Microsoft does have a clear monopoly in the operating system market. It's when a specific individual or enterprise has sufficient control over a particular product or service to determine significantly the terms on which other individuals shall have access to it. Microsoft has not only been proven to have one, but was convicted of illegally abusing its monopoly in US federal court. From illegally preventing PC venders from selling computers with other OS's installed to killing Netscape, these actions would not have been illegal if not for the monopoly Windows enjoys in the marketplace.
When people criticize Microsoft and Apple for not being open, they're entirely different contexts. Microsoft rejects compliance with most open (or licensable) standards such as Java, XML, Javascript, CSS, OpenGL, GCC, and so forth because they inherently promote interoperability with competitors. As a monopoly, the company profits off lack of competition rather than letting the merits of its products stand on their own. It's interesting that in most areas where Microsoft has no monopoly and is forced to compete, it's a dismal failure.
Apple not only embraces and contributes to open standards, but develops a good amount of its own proprietary technology as well, some of which it's opened (WebKit, Bonjour, OpenCL) to others. Apple is closed in its control of the full vertical solution of tying its Mac hardware to its OS X operating system to its iLife, iWork, and Professional suite of applications. Apple's brand and quality is based on the fact that its software supports only its own hardware rather than every box out there. In fact, I'd say Apple is more open to developers than Microsoft because every Mac Apple sells, from the MacBook to the Mac Pro, includes a Developer Tools DVD with IDE's such as Web Objects, xCode, AppleScript Studio and so forth.