re: minimize costs
There is more to cost than purchasing software. Where FLOSS is a strongly competitive solution, the choice is obvious.
On the other hand, for $250 / user you can buy QuickBooks, enter data very efficiently, and send a backup file to your accountant, who can restore it into his QuickBooks. You don't need to save much of your own time to justify $250 plus the cost of Windows, and you don't even want to think about what your accountant would charge to port data from what you send him compared to a minute to restore your QuickBooks backup file.
I'm not worried about Intuit going out of business, but plenty of Open Source projects have forked or simply lost the developer(s)' interest. Mambo, anyone? Regardless of source availability, none of my clients can read it, and none would be willing to pay me to maintain an abandoned Open Source project.
As for document formats becoming unreadable, I have no worry about an .xls or .xlsx file being read well into the future. What can you do with a GNU Oleo spreadsheet file?
And the original posting mentioned free but non-open source Hamachi and video drivers. Open Source is nice, but free and works well but closed source is no different to my clients.
