I believe he will slowly transition into other things rather than being an actor. Take a look at his profile on imdb, look at all of the films he has produced. I know many of them he has also had the lead role - but what is to stop him doing both for a long time yet.
I don't feel Will Smith would need to do anymore movies - from the amount of films he has starred in - he should be able to last a long time on that kind of money.
It has to be extremely fulfilling to create your own work, laying a foundation for others to follow in your footsteps. Mr. Smith may have his own company that rivals the old studios like Paramount, in the future.
