Envision an alternative reality in which development of FOS software, let's say Linux, OpenOffice, etc., predated Microsoft's rise to power. In that alternate universe, the FOS tools got widespread adoption. Services sprung up to support them, in line with the idea that you can make money from open source by providing quality support and services for a fee. Because of its widespread adoption, documents are exchanged as a norm in OpenOffice format.
Now, along comes a commercial entity that says, "Our $500 office software and $350 operating system is the way to go."
They would get nowhere, for reasons like lack of widespread support, lack of de facto standardization, etc. And of course cost would argue against them.
But in our universe, the commercial software got traction first and, in a sort of positive feedback loop, as they made more money they wielded more power and increased their influence and made more money.
So FOS fights an uphill battle and much of that battle isn't really based on cost so much as power and influence, especially in high government and corporate places. When the IT shop suggests open source, MS doesn't drop in to visit with the programmers; they go right to the top, suits talking to suits, and before you know it we have things like Australia mandating MS "standards" for government.
As an individual, I use Linux, OpenOffice, etc., exclusively. As an individual, proprietary software suits have no interest in buying me off. I can provide my own support and to me up-front cost is all the cost, and makes a big difference. But the corporate and government worlds are hardly the same. I sincerely hope FOS will make more and more corporate inroads. But it's a tough battle against powerful foes.