I suppose it depends on the field in which he was writing, and the actual thing he was examining; the title, after all, will have been a mere simplification of a great deal of work.
At least one would hope so.
That said, a friend just finished her PhD in English Lit at a university that shall remain nameless, and I was utterly blown away by how short it was. Judging by its length alone, it would have qualified as a mere MA thesis (or, just possibly, an MPhil) back in the day.
I do tend to think that PhDs are becoming a diminished currency. 😐
/grumpy old man