I nodded politely, made the equivalent sound.
What I didn't say.
"My *niche*? I spent fifteen years building a career in this field when almost nobody knew what it was, when you couldn't study it at university because the courses didn't exist, when it was an open slate to be anything you wanted any way you could be. Your niche was whatever you could carve for yourself. I went into it because I loved science with a passion, but I loved art, and writing, and theatre and media too, and I was good enough at all of them that I could become better with training and practice. In what other field could you do all these things at once, and touch people's dreams in six thousand different ways?
"I didn't leave it because I wasn't any good at it, though you can always secretly wonder how much of what you're praised for is just elaborate misdirection from your flaws. I left because I was tired, tired of the great battle for people's opinions that the mass media has become. And I left because of envy - envy of the other science communicators I saw who were fresh and energetic and confident, and succeeding where I had never been able to. For all I know they too are hanging on to their confidence and success by the skin of their teeth, hoping nobody notices the giant gaping chasm below - but I couldn't believe it of the crowds of happy chatting people I saw at the rare industry gatherings I managed to attend. To remain was to slowly poison myself.
"I didn't fail to fit the career, to fit the 'niche'. Rather, in the end, I failed myself. I was broken, and couldn't bring myself to try yet again."