If a company owned 2 plants, one inefficient and one efficient, and on the day before the reg takes effect, both plants are making money. The day the reg is effective, the company now has to figure out how they are going to comply. At the end of the day, if making the old plant efficient costs too much, they will close it and apply the credits to the new plant and sell off any excess.
As I said, this is one arrow in the quiver - what is so beastly about it from your perspective? Your point seems to be that I haven't proven a market-based system is better than a command-and-control system. Why is it one or the other?
Note, I learned about the cap and trade from this guy - a supposedly liberal economist: http://gsppi.berkeley.edu/faculty/lfriedman/lee-s-friedman