As you know Catholics are BOUND and MUST ACCEPT ALL Church teachings, both infallible and non-infallible.
If Limbo for Infants was a Church teaching we would be bound to accept it. However, Catholics have always been free to believe in Limbo for Infants or not. Tradition with a small “t” or common teaching is not a Church teaching.
The other issue is that a teaching of the Church cannot be cancelled. Limbo is not a Church teaching because it never has been.
Here is a quote from the Vatican paper (publication authorised by Pope Benedict XVI) titled The Hope of Salvation for Infants Who Die Without Being Baptized:
It is clear that the traditional teaching on this topic has concentrated on** the theory** of limbo, understood as a state which includes the souls of infants who die subject to original sin and without baptism, and who, therefore, neither merit the beatific vision, nor yet are subjected to any punishment, because they are not guilty of any personal sin. This theory, elaborated by theologians beginning in the Middle Ages,
never entered into the dogmatic definitions of the Magisterium, even if that same Magisterium did at times mention the theory in its ordinary teaching up until the Second Vatican Council.** It remains therefore a possible theological hypothesis**. However, in the Catechism of the Catholic Church (1992), the theory of limbo is not mentioned. Rather, the Catechism teaches that infants who die without baptism are entrusted by the Church to the mercy of God, as is shown in the specific funeral rite for such children…
- The idea of Limbo, which the Church has used for many centuries to designate the destiny of infants who die without Baptism,** has no clear foundation in revelation**, even though it has long been used in traditional theological teaching…
24…As for the expression “Limbo of Infants”, it was forged at the turn of the 12th-13th century to name the “resting place” of such infants (the “border” of the inferior region)…
26…Together with Catholic theologians of the Augustinian school, the Jansenists vigorously opposed the theory of Limbo…Papal interventions during this period, then, protected the freedom of the Catholic schools to wrestle with this question.** They did not endorse the theory of Limbo as a doctrine of faith**. Limbo, however, was the common Catholic teaching until the mid-20th century…
90**…A major weakness of the traditional view of Limbo is that it is unclear whether the souls there have any relationship to Christ**; the Christocentricity of the doctrine seems deficient. In some accounts, the souls in Limbo seem to have a natural happiness that belongs to a different order from the supernatural order in which people choose for or against Christ…
- Where sin abounded, grace superabounded! That is the emphatic teaching of Scripture, but the idea of Limbo seems to constrain that superabundance. (The Hope of Salvation for Infants Who Die Without Being Baptized. The International Theological Commission, Vatican City, April 20, 2007. at campchabad.com/roman_curia/congregations/cfaith/cti_documents/rc_con_cfaith_doc_20070419_un-baptised-infants_en.html#_ftn2 viewed 02/07/09)
Thus, the Vatican does not really want to teach that there is a place called Limbo, admits that it is not in the Bible, admits that it came about in Middle Ages (hence was not an original teaching of the church), and that it does not know what prophecy teaches about what will happen to babies who die without baptism.