Mr. Spock? Yes. He had no doctorate.
He may have had one but he was a serving military officer. He went by that title. That is the proper protocol. (Anyway its a TV show!) I know military officer with PhDs. If still in uniform I never call them Dr Captain, Colonel or General (or Captain, Colonel or General Dr!), if out of uniform then Dr so-n-so. If I know their pervious rank out of respect of for that rank I still call some of them by that rank until they tell me not to.
Of course they all have to call me the “Nameless One “ and avert their eyes!
Well, not by erf standards. But in a galaxy (63 and a half FORD GALAXIE 500 with a 427 dual quad) far fa......... Nap time. ;-)