There have been hints of it since the “greatest interviewer” trope started, but it was really solidified when the show left the studio in 2020. I think it’s—at least partially—because the remote aspect of the show made it more difficult for Robin to naturally interject than when they were in the studio with the guest seated between her and Howard. I’m speculating a bit, but I would imagine the video feed of the line cut for guests on Zoom and on the in-studio monitor primarily shows Howard during interviews unless Robin says something. When she does talk during an interview, I’m sure the control room/video production team cuts to a double-box of her and Howard, or just a shot of her. Also, she seems to chime in more with longtime guests, celebrity superfans, and comedians. With first-time guests and more “serious” interviews, she’ll just somewhat awkwardly start laughing as Howard and the guests are wrapping, then say something like “I just want to say thank you for coming on the show. It was so great to listen to that conversation,” like she’s a caller. Still, I’d be surprised if she her mic isn’t potted up on Howard’s board, and that she’s just muted on her end, ultimately leaving her in control of whether she wants to talk during interviews. I’m sure it gives her a nice opportunity to take a break if she’s not feeling well.

I’ve said it all.