I once read where the celebration of the Nativity was largely a Marian feast in the early centuries.
In fact, Candlemas, once known simply as the Purification of the Blessed Virgin, was also understood to be primarily a Marian feast, albeit, never losing the focus upon Our Lord's presentation in the temple.
After the Second Vatican Council, the emphasis was changed and the feast was designated as "The Presentation of the Lord". The reform dictated that every liturgical celebration be Christological in focus, as if it hadn't been before? In retrospect, some of the reforms emanating from the Council seem an attempt to take away from devotion to the Blessed Virgin.
Most likely to satisfy the 'separated brethren' of the protestant reform, as if the Catholic Church had previously exaggerated devotion to the Blessed Virgin. How strange, since the Orthodox esteem and honor Our Lady far more eloquently and devoutly than anyone else, except for the Latin rite - up until Vatican II.
I wish someone more learned than I would discuss this subject - if they have not done so already, say Don Marco, or Fr. Zuhlsdorf, yet maybe Athanasius should do it.
I've always been disappointed that some of the feasts of Our Lady have been downgraded - or suppressed, while others have had the focused changed. On December 18 there once was a commemoration of "The Parturition of the Blessed Virgin Mary" a feast in anticipation of the Nativity, now obviously supressed.
At least the Church continues to refer to the Marian character of Advent - perhaps only the Hispanics really understand it, with the devotion of Posadas.