I agree that the CDM mechanism is a good idea and that it's an important part of the Kyoto framework, but it's a part. The transaction costs for CDM projects are high, including a lot of senior executive time to actually pull them off. Hopefully that will come down over time.
The other thing is that unless the investment is close to their core business, it's hard for a lot of businesses to say that's where they should go. Your core business is your production process, your marketing process. For some businesses it's a natural; for others it would be quite a stretch.