Actually, the church couldn't dump limbo. Because if unbaptized babies went to heaven, then there is no original sin and the whole basis of the Catholic Church and its depiction of Christ's redemptive powers collapses. So limbo survived, a religious deux ex machina.

You've confused purgatory with limbo. Purgatory is where people go before they get into heaven. Limbo is where babies go if they die without being baptized. The Phantom Zone is where a lot of Kryptonians go. (Thank you 12 years of Catholic school and lots of comic books instead of catechisms.)