It's been long understood that typically the big cost in software isn't in attainment but ownership. The average cost of a Windows client license that comes on a new PC just isn't that much money over the life of the device.
Yea, however you want to slice it, money isn't a good argument for Linux adoption. And I need to be able to access Excel from any of my PCs. Open Office won't cut it in my line of work.
That's just my haypenny's worth though. I'm sure some folks here enjoy tinkering with Linux. I just don't have the time.