I've always thought that the revival of Stoicism is because 20th century philosophy messed with our heads to such an extent that we were left with an empty husk of our former selves, like ghosts floating in a meaningless world, and all we could do was laugh at ourselves to exhaustion lest we commit suicide.
No, I think it's a reaction against the new-agey types that pick up stuff so often from Eastern philosophical and religious traditions. Basically it's new-agey stuff for people that would never be willing to conceive of themselves as anything like a new-agey person.
Maybe I'm just talking about myself.