My first thought is to wonder if the world that John Calvin lived in didn't care deeply with the philosophical questions about freewill. Sure it was discussed by the Romans and others previously, but maybe this just was just watered down or forgotten by the time of the reformation.
When you look at people downstream from Calvin, such as the 1600s Puritans and even modern PCA Presbyterians, they tend to not be overly evangelical. They believed in "the elect," and God would bring those to him with irresistible grace. Calvinist missionary work is still very different from the born-againers looking to get people saved.
But I don't fault the ideology in general. To believe in an absolute all-powerful god, that god would have to know the future, while also allowing the free well of creation to make that choice. There are paradoxes in all fields, including mathematics with set theory and varying sizes of infinity.