How many of those box office record movies will be remembered 20 years from now? Every great actor has appeared in at least one iconic film role. Will has not had that role yet (In "Ali" he was great, but the movie was crap).
The only blockbuster movies of his that I've ever liked is "I Am Legend" and "I,Robot" and even they had so much potential, yet failed to deliver on their "film classic" promise. Another movie of his I liked was "Six Degrees of Seperation".
Smith has delivered many likable performances, but has appeared in crap. "Independence Day" is one of the most overrated movies ever.