That's such a perceptive question, Michelle. In fact, I wrote this story in part because it seemed most of these journalists weren't getting they engagement they deserved given their stellar--and often spectacular--work and credentials.
A lot of it may reflect that Medium killed its "house" publications devoted high-quality journalism (like Gen, Ascent, and Elemental) and stopped paying top journalists like Susan Orlean and Meghan Daum to post regularly. Those changes seemed to drive away not just writers who contributed to the now-dead pubs but a lot of people who appreciated great journalism and joined to read it. There isn't the audience here for journalism that there once was.
The low-clap level may also reflect that the listed journalists tend not to promote themselves either directly or indirectly (by writing for varied pubs that would put their work in front of more potential clappers and commenters) and that their level of engagement (by clapping for and commenting on others' stories) is relatively low. The quality of their writing is so high you'd think these wouldn't matter, but they seem to matter a lot.
All of is frustrating in part because I keep reading posts that say things like, "There's nothing good to read on Medium." There is, but if Medium isn't promoting it--and journalists themselves aren't heavily promoting--it can be hard to find.Thanks a million for picking up on this subtle point.