Fam you have to understand we live in a different time, and Kevin Hart's situation isn't the same as his predecessors. The people you named are actors and with the exception of maybe Eddie they don't own their own works - they don't own most their work,the studio does which is something Kevin champions against giving up. They never had Nike shoe deals, or massive Netflix deals (as it didn't exist in their time, Chris Rock is the only exception). Tyler Perry according to Wikipedia, is worth $600 million and none of his movies are blockbuster smashes the way Kevin's are.
You have to understand it takes time. And a billion dollars isn't what it used to be. Eddie Murphy, Chris Rock weren't making $32 million a year in their primes. Nor did they own businesses as successful as Kev's. Twenty to Thirty years is a long time and by then even if Kevin Hart chooses to get behind the camera, I'm confident he'll become a billionaire. Anything is possible.