How often do you have occasion to talk about the Trinity, outside of a formal setting?
The Trinity is significant, but most people, even good Catholics, are simply overwhelmed.
They accept it for the mystery it is.
Mostly because it is presented as totally irrelevant to our lives as Christians and just a thing that concerns God, as opposed to vitally central. A correct understanding og the Trinity, the Incarnation, and our Theosis/Sanctification by grace are all intimately and indissolubly linked. That's why there were so many councils solely about these issues. If people are never taught to understand our reconciliation to the Father by conforming us in the image of the Son through the work of the Spirit, it will all remain an obscurity.