Exactly and one further point theologically speaking the Rosary is not the sum totality of the Faith, if it were, what did our forebears in the Faith do until the time of St. Dominic i.e. before there was a Rosary ? (I pray mine everyday for the fulfilment of the requests at Fatima !)
You're not exactly correct. The Rosary does sum up most of our Faith, at least in its essentials.
Apostles Creed - Cover the important dogmas right there -- at least the ones the Apostles thought important!
Our Father - The one prayer Our Lord taught us personally
Hail Mary - Angelic Salutation, half of it is in Scripture itself
Glory Be - Doxology of praise to God as Trinity
O My Jesus - Prayer the angel taught the shepherd children to say, for the salvation of souls
Hail Holy Queen - Beautiful prayer to Our Lady, which is another hallmark of Catholicism (devotion to the Blessed Mother and seeking her intercession)
The 15 mysteries of the Rosary cover most of the main dogmas of our Faith. "Who by his life, death, and resurrection has purchased for us..."
You need not ask, "What did they use before the time of St. Dominic" because we're not in the time of St. Dominic. To paraphrase Gandalf, the Rosary "is never late. It arrived exactly when it meant to."Seriously, God's Providence gave us the Rosary exactly when it was needed. It would be needed on a "from now on" basis, which is why it's so important to this day.
The whole world gives witness to the fact that the Rosary is the quintessential Catholic prayer. When people see a Rosary, they know they're dealing with a Catholic (or at least a Catholic wannabe/cultural Catholic).
No one mistakes the religion of someone carrying a Rosary.