I agree however that there are people who haven't chosen to do that who have shown that ability in other ways. And there are people who have neither a college degree nor any long term project in their history which often indicates they are unwilling to put up with any inconvenience.
But the message that there is no silver bullet that will make sure all of your employees are "great" is true. If you assume that credentials are that bullet you will eventually get populated with a bunch of highly credentialed and ineffective bozos who will drive out the good people and leave behind an empty husk of a work force.