We are discussing what someone would use when writing about a hypothetical person.
And that changes it how? It's insulting to misgender someone, though I can understand how you'd think that there's no harm in insulting someone hypothetical.
I suggest you do some research on the history of language
Per your suggestion, "they" has been used to refer to a singular person since the 14th century. "He" is currently masculine-only. I apologize if you misunderstood my use of "never" to refer to things around the 18th and 19th century (when it apparently was considered bad to use "they" in the singular) when I presumed that there was an implicit limit to modern usage of English.
pronouns are really nothing new. he/him has meant a male person for hundreds of years, didn't it?
Either a male person or a hypothetical person whose gender is unknowable.
Someone with undetermined/unknowable gender would use the pronouns they/them, never he/him.
We're not discussing what someone would use for themselves. We are discussing what someone would use when writing about a hypothetical person.
If you believe that he or him would never be used in this case, then I suggest you do some research on the history of language.
Edit to clarify: And by history, I include recent history, meaning usage by people alive today, who learned it in school not terribly long ago.
And that changes it how? It's insulting to misgender someone, though I can understand how you'd think that there's no harm in insulting someone hypothetical.
Per your suggestion, "they" has been used to refer to a singular person since the 14th century. "He" is currently masculine-only. I apologize if you misunderstood my use of "never" to refer to things around the 18th and 19th century (when it apparently was considered bad to use "they" in the singular) when I presumed that there was an implicit limit to modern usage of English.