Should be until they win the election. 
It's a method to get folks used to a new GST rate, after folks
get used to it, they remove the GST credits, folks won't even know
it's gone. But then, they would have already made 7% extra.
If you spend $1,000 a month, the GST they earn from you a year
is $840. How much of GST credtis do they give you?
A lot of people don't realise how much the government can
make.
They only see the $100 rebates every year and think they are
getting a good deal from the government.