To undertake what they call land remediation prior to rebuildings house, I believe they have to heavily compact the ground with pile drivers, among other things. It's a lot more expensive than building a house in the regular way, and since many of the eastern suburbs have been severely affected by liquefaction twice in 6 months now, there's no guarantee it won't happen again. And as for the sewer and water pipes, and underground power cables, the entire infrastructure gets badly damaged every time the soil liquefys.