I disagree. We had a candidate talk the talk when we were experimenting with different interview methods. They came in and used a lot of team time to start learning the system and stack. And continued to use the team's time, costing real productivity. They lasted a quarter or so. Not only did the team lose out on productive time, they lost morale by having to support a team member who was not getting up to speed and had to have their work redone and an couple members lost more morale when the newer person was let go. It was a net loss to bring in the new poor performer. I've seen it play out similar more than enough to be convinced that the adage is accurate.