IF ONLY...
...introducing Open Source into an organisation was that easy. Yep, Open Office is good and works great at home, but large organisations usually have IT departments who decide what goes on users' machines, and they're not likely to support a mixture of operating systems if they can help it (or even different applications).
Neither is it a 2 minute job to test replacement OSS applications for compatibility with all /existing/ systems. E.g. in somewhere like the NHS - is the GEM software used to authenticate NHS smartcards available for Linux? If not, that's a showstoper, and that's just one example out of 100's. On top of that, all the helpdesk support is usually geared up to Microsoft and the top tier of decision makers haven't got a clue about what the 'problem' is with Microsoft anyway.
In short, the problem is systemic - proprietary formats such as Microsoft's have come to be seen as 'standard' (e.g. Explorer) and they're extremely difficult to extract now they've got their insidious multi-tentacled grip. Hmmm - almost like a cancer, come to think of it...
Anyway, having spent a lot of thought on how to get more OSS into public organisational use, I have come to the conclusion that the only realistic way is for the procurers of public software to simply insist upon compliancy with open standards. If they'd done this in the first place, neither Explorer or Office would be in great use, for a start.