What a load of balls
We may not be sticking Ubuntu on every desktop, but open source is not ubuntu. Open source permeates right to the heart of all parts of UK biz, from the financial house using RabbitMQ, to the plethora of web developers in the UK using a variety of open source frameworks, often for very small businesses.
What we tend not to do is spend money for the sake of spending money. Putting people trained in a lifetime of windows in front of ubuntu costs money and productivity, and besides, every computer comes with windows anyway. Its more hassle and cost for an IT dept to request linux, or receive rebates on MS licences or deal with the deluge of user support queries, than it is to just accept the cost.
Its not ideal, but MS have a good grip on the desktop.