Hollywood is different these days. Whereas in the past people would flock to see a certain actors films, today it's all about the size of the franchise, how much cgi is in a film, how unrealistic it is. With a good agent people like the Rock insert themselves in established franchises and the following he has elevates it that little bit more. His solo outings are nowhere near as successful as the established brands.
Put him, a Chris Pratt, Chris Evans etc in the 80s or 90s they wouldn't touch arnold, sly in their peak