A report by the Standish Group indicates that adoption of 'open source' has caused a drop in revenue to the proprietary software industry by about $60 billion per year. That's not a huge amount of money compared to what has been lost though the misselling of mortgages, but it is still a lot. The report identifies the value of these 'open source' products to be about 6% of the world market for software. Unfortunately, the Standish Group doesn't believe in openly sharing its research, instead selling it for $1,000...
In an ideal world, we could presume that the companies that are not spending this money on proprietary software are spending it wisely. I would be worried, however, that senior decision makers will not understand the cost savings possible in IT at the moment. Thinking about an IT department in a large organisation, it is unlikely that the management are going to want to reduce their spending, as this will make them less important... and we can assume that managers don't want this. It will be much easier to stick to the proprietary route and keep spending money.
Now is the time, for those suited to it, to get out into the corporate world and explain to the most senior management the cost savings that can be achieved through using free software. That will mean that the squeeze will be put on IT departments to come up with more sustainable plans for their purchasing. This will create more demand for free software consultants and paid posts for free software programmers and experts.
I have held for a long time that the free software ethos means that you should be making money out of what you are doing, not what you have done. If this research group can sell a piece of paper of $1,000, maybe we can make a bit of money out of consulting.