There are intercessions, called “Preces” in the Roman Breviary, BUT, and this is what is of interest to the OP, they only occur on Wednesday and Friday of Lent and Advent and Ember Days. This would explain why they would be omitted for the Majority of the year, and why they are currently being omitted on Divinum Officium, which is quite air-tight in it’s rubrical fidelity.