There are other amendments that cut back on some of the worst pork.
The Australian Constitution in section 55 forbids tax and spending legislation to deal with any other subject. If an Act includes other material, it's void, it has no effect.
This prevents the American situation of omnibus bills, rider amendments and the like.
We still get pork barrelling here; but between S 55, fused executive and legislative and strict party discipline, the political incentives are differently structured for individual politicians. It creates a stronger check on profligacy.