"DFC Intelligence will be releasing detailed forecasts in June. As mentioned we will be releasing multiple scenarios for the industry, and these scenarios will be constantly revisited over the next several years. Right now, our best case scenario for each system has the Xbox 360 at 40%, the PlayStation 3 at 50% and the Revolution at 35%. Obviously these scenarios are mutually exclusive, the best case scenario for the 360 is definitely not the best case scenario for the PS3 or Revolution and vice versa.
The main point we stress with our forecasts is flexibility. The interactive entertainment market is driven by hit products that simply can not be created by will, even from the largest company with the best business plan. Nintendo once looked invincible, now many have written them off. It is surprising how big players can face sudden falls from grace. Beware of any publisher that puts too much investment into any one system. Successful publishers will have their eggs spread across many baskets. DFC Intelligence releases all kinds of numbers designed as roadmap for the future. Nevertheless, predicting the future is something we always do with the caveat that we could easily be wrong. Proceed with caution."
This is a very long winded article, but contains some very good points. As the article points out these forecasts are always in motion.