As noted above, weekday Liturgies celebrated in my parish by the previous two presiding priests, would have no sermon at the appointed times, after the Dismissal, the priest would come down from the sanctuary with an "Happy nameday to those who celebrate today..." sometimes mixed with an anecdote about the saint's life or the significance of the feast. It drove me nuts. Thankfully, our current priest will give a sermon even on weekdays.
I recall there was a practice in Greece, probably a remnant of the Ottoman occupation, which may have lasted through the 1960's, at a time when many of the priests were only educated in ecclesiastical schools, not graduate schools of theology, wherein these priests never gave sermons. Sermons were only given by itinerant preachers, often layman, who had graduate theology degrees, and the bishops. I have read that the number of priests who are not educated in theology schools in Greece has been significantly reduced in the past 20 years or so. Metropolitan Kalistos of Diokleia (Timothy Ware) discusses this matter in "The Orthodox Church."