De Villiers told South African newspaper Beeld that he finds it amazing how the South African teams blow hot and cold within the same 80 minutes.
"It happened again last weekend when so much good work was made undone by sheer ineptness," De Villiers told the newspaper.
"It's not the fault of the new laws that some of our teams are struggling to play with the same urgency and intensity for even 60 minutes.
"The experimental laws did force some teams to make a mind shift because they cannot now rely only on structure as the foundation of success.
He added: "That's where the problem lies. Teams that were accustomed to playing strictly within a structure also limited the inventiveness and independence of their players.
"I don't think all our teams have made the necessary mind shifts. That is why they play such varying types of rugby in the same match.
"We'll have to adapt better and more quickly to the challenges that the experimental laws have created. At the same time, players must be encouraged to rely more on instinct than on rigid prescriptions."
The Bok coach pointed to the defensive records of the various teams, with only the Sharks and Stormers scoring more tries than they conceded.
"Defence wins matches and it goes hand in hand with the correct disposition," De Villiers said.
The Bulls, the defending champions, have the worst defence record of all, having conceded three times as many tries as they have scored.
However, De Villiers said the Bulls had shown signs of brilliance in last week's match against the Chiefs.
"It is encouraging. All they have to do now to maintain the same pace, urgency and intensity for at least 60 minutes is to believe in each other."