It was. But by "contemporary" I meant "contemporary with Mark." Literature is not the same across the centuries.
How about
Galatians 2:9-14?
Paul's version:
[A]nd when they perceived the grace that was given to me, James and Cephas and John, those who were reputed to be pillars, gave to Barnabas and me the right hand of fellowship, that we should go to the Gentiles, and they to the circumcision. They only asked us to remember the poor—which very thing I was also zealous to do.
But when Peter came to Antioch, I resisted him to his face, because he stood condemned. For before some people came from James, he ate with the Gentiles. But when they came, he drew back and separated himself, fearing those who were of the circumcision. And the rest of the Jews joined him in his hypocrisy, so that even Barnabas was carried away with their hypocrisy. But when I saw that they didn’t walk uprightly according to the truth of the Good News, I said to Peter before them all, “If you, being a Jew, live as the Gentiles do, and not as the Jews do, why do you compel the Gentiles to live as the Jews do?"
All tell version:
[A]nd when they perceived the grace that was given to me, James and Cephas and John, those who were reputed to be pillars, acted friendly enough. They agreed that we should go to the Gentiles, and they to the circumcision. They asked that we should remember the poor, which very thing I was also zealous to do.
Later in Antioch, Peter took the side of some men from James in a disagreement with me over table fellowship with Gentiles. Barnabas did, too, along with the other Jews. I told Peter off to his face, in front of the others.
Mark-up of Paul's version: show, forward, resolution, and tell (i.e. plain exposition).
tell
[A]nd when they perceived the grace that was given to me, James and Cephas and John, those who were reputed to be pillars,
show
gave to Barnabas and me the right hand of fellowship,
tell
that we should go to the Gentiles, and they to the circumcision.
forward
They only asked us
resolution
to remember the poor—
tell
which very thing I was also zealous to do.
forward
But when Peter came to Antioch, I resisted him to his face, because he stood condemned.
resolution (to end of quote block)
show
For before some people came from James, he ate with the Gentiles. But when they came, he drew back and separated himself, fearing those who were of the circumcision. And the rest of the Jews joined him in his hypocrisy, so that even Barnabas was carried away with their hypocrisy.
tell
But when I saw that they didn’t walk uprightly according to the truth of the Good News,
show
I said to Peter before them all, “If you, being a Jew, live as the Gentiles do, and not as the Jews do, why do you compel the Gentiles to live as the Jews do?"
But it has nothing intrinsically to do with whether a character is introduced qualified or unqualified.
The issue you raised was the hypothesis that Mark may have been clumsy and unreflective in not qualifying Pilate. I presented an alternative explanation to clumsy lack of reflection. That does strike me as "having something to do" with how Mark introduced Pilate.
You and I have no disagreement about the fact that Mark doesn't explain who Pilate is (before or after the character is introduced). We may disagree about Mark's competence in introducing Pilate that way, indeed in never explaining who Pilate is, which in turn bears on the topic.
So far as I can tell, it is uncontroversial that an author may omit an introduction or later identification because the author believes the audience already knows who the character is. You, not I, introduced a second possibility: that the author may omit such material because of unreflective clumsiness. Uncertainty about the matter thus established, I proposed a third possibility, where, like in your first hypothesis, Mark displays skill.
I gave ancient analogies for virtually every point in the OP except for the ones under discussion (the introduction of Simon and Pilate); I ignored analogies for these examples simply because I thought they were so obvious. There are plenty of ancient analogies to be given, and I may add them to the OP for clarity.
Apparently, you feel that the first hypothesis requires contemporaneous examples, and good for you to have provided them. However, your second hypothesis seems to have required no examples. I don't disagree: stupid is eternal. But since my third hypothesis is rebuttal to that unexampled second one, it's unclear how much example I owed. I claimed only something that is within the demonstrated expressive capability of human natural language, which capabilities are, so far as we know, as eternal as stupid; an inherent feature of our species, and not anything requiring craft innovation so late as historical times are in our species' existence.
No biggie; Paul furnished the requested example in his little short story.