Pruning the calendar of feast days gets things exactly backwards, since historically speaking Mass was celebrated firstly on Sundays, then on the feasts of martyrs and other saints. The development of the whole suite of feasts and seasons around Easter and Christmas paralleled this – hence the days of Lent have proper Masses, as they lead into the celebration of Holy Week. Penitential times such as the Ember Days early on acquired proper Masses also. But the very last days in the calendar to acquire their own Masses were ferias, and in two senses they never did: in the Traditional Roman Rite, on all free weekdays, the Sunday Mass was either repeated, including its readings, or a Votive Mass of some sort was celebrated – hence the way that old Missals specified which Votives were to be said on which weekdays. Some mediæval Missals, such as the Sarum, provided Epistles and Gospels for Wednesdays and Fridays, so that, if those days – which were once both fast days – were without any feast, the Sunday Mass would be repeated but with those readings instead.
All this changed in 1969 or thereabouts (for experimentation had begun earlier), when an entirely new Lectionary was given to the modern Roman Rite. Some of its features – such as extending to Advent, on the analogy of the Lenten Masses, daily readings and prayers and chants for weekday Masses; and doing the same for all of Christmastide and Eastertide, based to some extent on the ancient provision of proper Masses for each day of the Easter Octave – were logical extensions of existing practice. Given, too, the precedent of providing Wednesdays and Fridays of old with their readings, to provide ones for every day could be seen as reasonable.
However, the Roman Rite is not the Byzantine Rite (which has had for over a thousand years a semi-continuous cycle of readings at the Divine Liturgy, such that almost the whole New Testament, except for the Apocalypse, is read through once a year), and the exaltation of the ferial Mass (most evident in Ordinary Time) that has gone with imposing a new Lectionary is in fact a reversal of the historical development, in that the readings (whether from the Proper or from the Common) for saint's days are now overshadowed by the panacea of semi-continuous Scripture readings.
I believe that this problem has arisen from confusion of Mass and Office. In the case of the Office, the exact contrary is true, in that the ferial Office is the older, and later rather overgrown with feasts: by reason of the structure of the Office, with a weekly system for reciting all 150 psalms, and a yearly system for reading a good deal of Holy Writ at Matins, there is an impulsion in the Office toward retaining the ferial and pruning the sanctoral Office. But in the case of Mass, I argue that the opposite is true.