I’ve always wondered why more Catholic clergy don’t preach a series. Even great homilists cultivate a message based on a set of Sunday readings in isolation from what was preached the week before and what will be preached the week after.
But we are given a Lectionary. We know the readings for next week, and the week after, and the weeks and months beyond that. We know the readings for the second Sunday in June, 2025. We have a fair confidence, at any rate. People like Fr Felix Just give us charts like this one so we can see the Sunday Scriptures at a glance. We know we’ll get five weeks of Galatians, followed by a month of Colossians, then some Hebrews, and then some other letters in sequence.
We can see the scope of Luke’s Gospel and borrow a basic Bible outline to see Jesus ministering in Galilee until June 23rd. Then the hinge of the whole Gospel: Jesus sets his sights on Jerusalem, a decisive turning point in his public life. July is all about being a follower of Jesus. Then we have a relentless series of parables and personal encounters, culminating with three November Sundays of Jesus in Jerusalem as the plot around him thickens.
Will Catholics in our parishes get this scope? Will they get June 29/30 preached as the turning point of Jesus’ whole ministry? Will they be inspired to find themselves and their life situations in those stories the Lord tells on the way to the cross?
Anybody out there ever experimented with a homily series, building up for two to six weeks? It would seem to make preaching prep easier. But there’s a lot of advance work to get that started.
Or maybe this is just too Protestant of an idea.
Catholic Sensibility 
I fully applaud your suggestion, and when preach to the English speaking community here in the parish I try to point up the continuity and links between each Sunday. However there are a few factors that can militate against its implementation. With our Masses for the Japanese parishioners, the celebrants for the Sunday Masses changed according to a rotation system that only the pastor seems to understand. In a recent month, including a visiting priest, there were four different celebrants for the most well attended – main – Sunday Mass. Further pastor and the assistants all have their own unique (??) take, own distinct way of reading/interpreting the Sunday readings. And finally, and this is perhaps the crucial point, there is still a profound indifference, coupled with ignorance on the part of some, of the structure and theological focus of the lectionary, be it for the Seasons (Advent/Christmas, Lent/Easter) or Ordinary Time. I still encounter priests who, in Ordinary Time, talk of their struggle on a particular Sunday to find a link between all three readings, even though it states clearly in the instruction at the beginning of the Lectionary that such a link doesn’t exist. Sadly the Lectionary is a still unexplored treasure house for too many priests.