Circumcision and Baptism (Col. 2:11,12)

One can see the force of the argument that circumcision is a fleshly covenant which is tied to the flesh while Baptism is a sign that communicates spiritual renewal and spiritual washing.  It is conceivable to think that maybe Paul is making a historic progression meaning that we move from circumcision, fleshly covenant, to baptism, a true spiritual realization, after Christ’s coming. So, why would people baptize infants if the Lord has changed the significance of the covenantal sign?