A small business or tradesman already pays a mountain of money. Any margin has 15% taken for gst, followed then by income tax for the operators, business tax for the profit margin, then a bunch of other stuff like acc etc. For every dollar earned, pretty much another dollar goes to the government. An extra levy would be a huge disincentive wouldn't it?
There is no additional tax collected. Whether you are taxed too much compared to the taxpayer standing next to you who knows, I’m sure that’s a matter of personal opinion and not much else. There is certainly a lot of evidence that tradies do cashies to avoid tax altogether, that simply is fact. Expanding the tax base as proposed squeezes the ability to do that a bit but certainly doesn’t stop cheats totally. In the second phase of our tax reform - that will not see the light of day unless this does - we have that dealt to through a combination of single tax rate, tax deductibility of home repairs and far better reconciliation of GST receipts. But that’s for the future. I think the important point here is that loopholes and tax cheating simply puts the burden on someone else. By hitting those really hard society is way better off.