We have been here before with IBM. During the 1970s and early 1980s it was known for its immense arrogance. It was almost a privilege, an honour, to own IBM equipment. Their style was, "We'll tell you what your budget is for next year then we'll tell you how to spend it."
Microsoft has not been that bad. The inner workings of Windows may well be closed, but there are plenty of interfaces that are published, to allow applications to be developed for the operating system.
So what if Microsoft's applications are able to use unpublished programming interfaces to make their software run better? There is a benefit in having Office closely linked to Windows. When a new patch is released, both the OS and the applications are updated simultaneously.
Unless your business demands the cutting edge, you stick with established standards.
A monopoly can be bad for innovation, but as a practising IT manager, standards are more important. If a PC supplier were to create its own version of Windows it could be disastrous.
I have to manage the IT for 1,300 users. It is a basic business requirement that files can be shared throughout our organisation and beyond. You could have the most innovative software on the planet, but if you can't share the data with the rest of the world then it is worse than useless.