If you know about writing and publishing, you know this statement is nonsense. J.D. Salinger continued to write and publish while living like a hermit.
When drafting my reply, I initially wrote something about Salinger having published short stories and novellas but only one novel, but I deleted that from my reply in draft and preview before I posted. I didn't think it supported my point and I agree with you.
Where did you see something about Salinger?