I used to be a big Microsoft only developer. It was a lot like having those blinders on that horses wear. You develop tunnel vision regarding new and different technology.
The fact is that open source is far more responsive to client's needs than proprietary software. The advantage that large corporations have over open source developers is organization and money. Microsoft can allocate resources (human and financial) to beat anybody in the market. The DOJ has only slowed them down. But open source is different. You can't 'get' the open source market. It has too many heads and hands. It is too fluid. The distribution of Internet Explorer is not an example of open source. It is an example of the power of freeware. Freeware = Marketing. That's all. The free distribution of IE was a market technique to destroy a competitor in a market space that has only begun to realize its potential: the internet. Killing off the other babies in the womb is the natural behavior of a shark. Microsoft has learned this technique well. As the internet age emerges, they are prepared to dominate.
Developers are among those at risk as Microsoft's sphere of influence increases. They will be enculturated in Microsoft philosophy and problem solving techniques. The history of computing will be replaced by the biography of Bill Gates.
The way to keep your skills sharp is to keep your mind free of influences. Make your own decisions and participate in open source development initiatives actively. Let people know about open source and what you are doing and why. The more people who understand the difficulties of prospering in a monolithic computing culture the easier it will be to overcome the darkness before us.