I would say that now the "sex icon" is more reserved for whores like Megan Fox and Kardashians who jump from dick to dick and post their plasticy assets for engagement.
Scarlett on the other hand always tried to marry and settle down, unfortunately she fell for people like Ryan Reynolds (who has the perfect match in Blake Lively, both egotistic narcissists). She never begged for instagram clicks or twerked for basketball players.
But if by "sex icon" you mean she is the most sexiest, the most perfect woman in Hollywood, then yes, I agree.