While the actors faces are intrinsic to our memories of those films, there is nothing in the films existence intrinsic to those precise faces and identities.
The existence of nothing hinges on Julia and Tess existing as dopplegangers except the plot of the film itself. And if Julia Real didn't act in Ocean's Eleven, her star needs not be diminished: she'd have taken some other project which could be a hit. Maybe even several in the time it took to film Ocean's Eleven in the real world.
The article's author's brain is wrapped up in la-la land and the cult of personality.