Of course it would be a prayer and it would have merit. But I don’t think it would be the best way to pray the Rosary.
I have been struggling with the Rosary for many years. I have come to believe that it is truly the best of all prayers next to the Holy Sacrifice of the Mass. One of the things that I have always disliked about the Rosary, I now believe is one of the reasons that it is such a powerful prayer. What I am talking about is the difficulty in repeating the same prayers over and over again and at the same time trying to concentrate on the mysteries. It’s hard. Like you say, it;s hard to keep one’s attention and focus. But I have come to believe that that is precisely why it is so meritorious. The highest form of worship is sacrifice. In the recitation of the Rosary, there is ever present the notion of sacrifice. Even after thousands of Rosaries, we still have a long, long way to go to pray this prayer perfectly.
There are several scriptural Rosaries that are helpful in praying the rosary well. I just came across one called, The Rosary, The John Paul II Method, by Robert Feeney.
In JPII’s method, a verse of relevant scripture, or other pertinent remark, is recited before each Hail Mary. Also, he sets forth a fruit to be prayed for in reciting each decade, plus at the name of Jesus in the Hail Marys he appends a clause related to the mystery. For example, in reciting the third sorrowful mystery, The Crowning with Thorns, when each Hail Mary is said, at the name of Jesus is added the clause, “crowned with thorns.” It goes like this, “and blessed is the fruit of thy womb, Jesus, crowned with thorns.” It is a clever trick to help us keep focused on the mystery we are contemplating. I like this better than listening to a recording, because it requires the reciter to do all the work, but I still do see that you can receive benefits from the recording method you describe, as well. Also, at the end of each decade, John Paul II recommends saying the Fatima prayer: “O my Jesus, forgive us, save us from the fire of hell. Lead all souls to heaven, especially those who are most in need.” (There are local variations of this prayer.)
More and more people are finding the Rosary, which is very encouraging. If enough people pray this powerful prayer from the heart, I believe God will bless the world in great ways.