One of the unforeseen consequences of too many owners owing too much is that it makes the whole scheme vulnerable to predatorial investors who, in extreme cases, can take control of the block and push through work that requires special levies, forcing more owners to sell. Once they have bought enough properties at knock-down prices, they then sell or plan the whole block for demolition and rebuild at a massive profit.
I assume that any developer can buy a unit and then take the strata to NCAT and get an order that the defects must be fixed.