I suspect Viggo will become like Daniel Day-Lewis in that he may take a year or two off between projects, but he'll keep getting approached by great directors with scripts he can't resist, so he'll wind up making four or five movies a decade rather than one or more a year. Day-Lewis has taken time off to be with his family and even had such odd jobs as a cobbler, but when his old friend Jim Sheridan or Marty Scorsese or P.T. Anderson come along with amazing roles, hey, he's a working actor again. Viggo will take time off to write his poetry or sail around the Mediterranean or whatever else he wants, but when the good scripts come calling, so will Mr. Mortensen.
Sean Penn said he was retiring from acting back in
1991 when his first directorial effort,
The Indian Runner, was released. Since then he has directed three more features but he's also had starring or co-starring roles in about twenty more and counting, including five Oscar nominations as Best Actor and two wins. Viggo was the co-star of
The Indian Runner, so he knows all about such sincere-at-the-time but ultimately empty statements that someone who fancies themselves an artist can make from time to time. He ain't gonna give up his art, his profession.