First of all, Jesus was not just you or me.
Now, also remember that anything happening in a synagogue then was just prayer, not regarded as real liturgy. Liturgy was what happened in the Temple, with sacrifices and offerings. Only after the Temple was destroyed, were the Jews forced to formalize congregational.worship in synagogues.
There were two ways to do readings. One was to ask an adult male of the congregation to sing a “portion”. You had to be able to read in Hebrew and sing the chant melody. It was an honor often extended to distinguished visitors or pious young men, and of course today, it is how a young Jewish man shows that he has become an adult, on his Bar Mitzvah day.
But if the person asked to sing the portion was a learned man or a rabbi, he was expected to give a little discourse on the reading afterward, whereas Joe Schmo would have just let the local learned guy give the sermon.
Jesus was apparently known to be a Schmott Guy, so he was asked to do more.
So if you are Fr. Distinguished or Deacon Distinguished, and you visit a parish, you might find yourself in Jesus’ position of doing the reading and giving the sermon. If not, then not.