Kingpins,You're post covers the two reasons why changes to NG...

Kingpins,

You're post covers the two reasons why changes to NG will occur.

NG was okay when only the well off were taking advantage.
Now it's used by too many people. ie average people.
The country can't afford that.

Public housing has not been helped by negative gearing - as your figures suggest. The property investor is chasing higher rents than the poor can afford too pay.
So the ball is back in the Governments problem box.

No need for NG.