TI, We all live within our means. That is not the issue. What is the issue is that SIA Cargo have reduced those means by not increasing housing allowance in line with the market rate.
I realise that it is, perhaps, a difficult concept for a non expat to get their head around but it is actually very simple. Expats gets paid a salary plus either housing allowance direct to salary or they have housing provided for them by the company. Either way, the salary element of pay should not be required for housing. Its the same the expat world over.
When I joined SIA Cargo, that was the case. Now it is not and many expats are actively looking elsewhere. Short term, that may have you clapping your hands but please bear in mind that expats are in Singapore because they are needed. You want to keep them, you listen to market forces.