That is very true. I've seen many articles in recent years from industry insiders speculating if the the days of "names" selling films is over. The bigger bet is on franchises now, which is why many of those A-listers and past-A-listers are trying to attach themselves now (like Tom Cruise doing The Mummy, which was supposed to kickoff a Universal Monsters Cinematic Universe). And probably not coincidental that, in 40 years, Denzel has just made his first sequel, with Equalizer 2, his own "superhero" film.
The one thing helping many of those big names, even older ones like Stallone and Schwarzenegger, is that they still draw overseas.