I have a lesbian friend who is in their 50's, has never been on T and other than her voice, she easily could pass for a man. She isn't trans and really isn't trying to look like a guy but she does. And IMHO most of it is how she carries herself, her mannerisms etc.
I do believe saying things like "Without T, after a certain age, most ftms will never pass" is simply incorrect and I hear the exact same thing on the MTF side. People think "I can take this pill/shot and transform without doing anything else", it's wishful thinking for most people. Yes HRT helps but that isn't the end of it.