Microsoft has a monopoly on the Windows kernal, which is the most commonly used kernal.
Ok, so group A has kernel A, group B has kernel B, and group C (Microsoft) produces kernel C (Windows) to rival kernel A and kernel B. Within a matter of years, kernel C is
the most popular kernel.
No other company makes operating systems which uses a Windows kernal except Microsoft, and they can charge whatever the hell they want because of this.
Yes, this makes sense. You create kernel C, it's your kernel C, nobody else makes kernel C, you can charge whatever you wish for it. Just because it is popular does not mean you own a monopoly. It just means you're very close to it, seeing as how now kernel A and B are rarely found in a household.
Kernel A and kernel B still exist, and are alternatives to kernel C. Products are still made for kernels A and B...
Microsoft does have a monopoly, and if they made it so their anti-virus is the only one that works on their operating system, they'd be illegally using that monopoly.
If OS X and *nix never existed, yes, Microsoft would have a monopoly. However, they do exist, as do other alternatives; thus, they don't have a monopoly.
(My use of the word 'don't have a monopoly' means do not have a full monopoly. They are close to monopolistic status, but they aren't there.)
If group C wants to produce problem-fixer C (the anti-virus) for their kernel, and not allow any other problem-fixers to work on kernel C, the 3rd party problem fixers can still produce for kernels A and B.
