Funny you should make this comment; it is what I was thinking on my drive home tonight. They also have no impact on the liturgies celebrated in the Eastern Catholic Churches which, like the TLM, also follow a fixed liturgical calendar.
One of the best changes to come out of VCII, however, was the expanded readings spread out over the span of 3 years. This has truly opened Scripture to those Catholics who don't make the effort to read their Bibles. In the Maronite Church, we have only one reading at Mass, usually from the Letters of St. Paul, followed by the Gospel. The advantage of a fixed calendar is, ironically, its repetition. We are currently in 'ordinary' time. But come September, we will enter the Season of the Holy Cross. In the Latin Church, it's only one day and then, only if it falls on a Sunday; whereas for us, it lasts for several weeks. And then we move into the Sundays of the Church, followed by the Season of Announcement and Birth of our Lord. How I love to hear the Gospel on the Sunday that celebrates the Announcement to Zechariah! The Season of Great Lent, in like manner, takes us through the miracles of our Lord.
This repetition is like a rhythm of the Church that we follow from year to year. It keeps us rooted in the faith of our fathers.
I agree with you. I like the yearly repetition of the old Mass. It seems easier to spiritual prepare for the Mass. There are hundreds and hundreds of wonderful old catechetical tools to study the faith or benefit from it keyed to the old Mass.
I also agree with you about the three year cycle of readings. We do get more scripture. No doubt about that. Sometimes I think they should have kept the Old Mass, but added the three year readings cycle! I heard a former SSPX priest say that once. Surprised me to hear it from him, but it makes sense.