Chadwick Boseman, Michael B. Jordan, David Oyelowo, Andre Holland and Mahershala Ali got next.
I agree with this post in theory but on the real, Chadwick and Mahershala are in their 40s. Hell, Andre Holland is 38 and Oyelowo is 41. The clock is ticking on them too. They're pretty much peaking as I write this. The older they get, the fewer roles they'll be offered. A Denzel or a Smith could get roles in their 40s and eat good, but that was on the strength of their past performances and box office receipts when they were much younger.
FEW actors who didn't make it big till their late 30s/early 40s will be able to have a career with consistent buzz going enough for them to really prosper like that. And I'd wager NONE of them are ever able to parlay that buzz into being a huge box office draw.
Only person I can think of with a similar trajectory is Jeremy Renner. His breakout role was in the Hurt Locker when he was already pushing 40. He was VERY lucky and a pretty much one-off case who was fortunate enough to have already secured roles in several major franchises by the time he was Mahershala and them's age.
Out of all them, the only one who really stands a chance at making it anywhere close to the old time major league players is Michael B. Jordan. He's young, people know him as an actor outside of a franchise, they LIKE him and women love him. ALL (races of) women love him and will watch his shyt just because he's in it. That's a huge selling point to these studios.