Actually, its an interesting comparison. I use ESRI products and more and more I am shifting to using free (such as Google) web and non-web products to do some display / mapping work. Why? Because, for one, as you said, every ESRI Arc 9.3 seat costs a shitload. Secondly, I can achieve a substantially similar result in half the time while leaving the license open for someone else. Will it come to a point that free/lower cost software solutions will eliminate ESRI? Maybe. Should they feel threatened? Absolutely. Their user base is already being eroded and users disgruntled. I can't seem to find many fans. So is it a fair comparison? On the cost, no. On the features and use - absolutely. They are both complementary and competitors.