Not that they were ever going to do much anyway. The principle of Keynesian stimulus is to provide public activity when the private sector retrenches, as it is now. Tax cuts in such circumstances just get saved. Via Domain:
The size of the Morrison government’s first round of tax cuts has fallen well short of expectations, as workers shun accountants and fail to make deductions, casting doubt on their impact on Australia’s sluggish economy.
…The Sydney Morning Herald and The Age can reveal that despite the new low and middle-income tax offset that promised to pump up to $1080 into the pockets of cash-strapped households, there has only been a modest lift in refunds.