We do have "pop scientists". While they're not all necessarily "groundbreaking" or "leading researchers", I wouldn't discount the impact of folks like Neil Degrasse Tyson, Michio Kaku, and Brian Greene.
In the UK, Brian Cox for physics/astronomy and David Attenborough in the natural sciences are likely responsible for enough recruitment that will probably lead to significant knowledge gains.
Arguably one might make the same case for Michael Faraday or Humphry Davy, who's fame in large part devolves from excellent and hugely popular public demonstrations of their work.
It's not that they didn't (necessarily) also do groundbreaking work. But they were phenomenally effective communicators.
Extended to writing, Darwin, Einstein, and Feynman could be similarly considered.