Exactly the point he keeps glossing over...
With 2x 580's comes more price, more heat, more power consumption, more noise....for very little performance boost...Most have already conceded that the 580's perform over all slightly better then the 6970's, but not enough to justify the cons.
Here's a few games where the 580's lose too, so you can see they don't always win...and last time I checked, Batman has Physix
http://alienbabeltech.com/main/wp-content/uploads/2011/09/batman-25.jpg
http://alienbabeltech.com/main/wp-content/uploads/2011/09/ss-25.jpg
http://alienbabeltech.com/main/wp-content/uploads/2011/09/COP-19.jpg