Although maybe he's wrong about Photoshop vs Gimp, I still think he is correct in saying that some programs just can't be done in an open source manner. A better example might be something like Second Life - there is no way that could have evolved the way most open source software evolves now.

Some things just require immense dedication and concentration from a large amount of people from the very start - and in an open source project, you can't get that until you have a sizable project already done.