Techies talk a lot about Moore's Law, but there's another economic law which Microsoft solutions also violate, and which open source threatens.
It's the law of mass production.
When any good goes into mass production its cost goes down. Microsoft has flouted this law for decades. In fact, today's Microsoft Office costs as much, or more, than it did 20 years ago, despite the fact that the number of users has grown exponentially.
Open source projects pass these savings on to the consumers of software. It's not just free to get. It's free to upgrade. And you only pay for open source when you need someone's help, for training, for implementation, for fixes. Then, you pay only for the cost of the labor you need.
For a scaled user this makes open source a real bargain. The labor costs exist anyway, even in Windows IT shops. The costs of transitioning to open source are manageable, and the later savings go straight to the bottom line.
This is not as true for individual users. For a consumer with a PC or two, the costs of Windows now includes some management services, and support. Even for a small network manager (and this includes many homeowners) there are education and training costs to be paid up-front, plus the possibility of big-ticket service calls down the line.
The natural answer is to capitalize these costs and pay them out over time. Automate the courseware, automate the delivery of updates and patches. Sounds great, doesn't it? Sounds like a business, right?
Sounds like Windows to me.