The problem is the marginal tax rate. That is what acts as a disincentive to work. At over 50% who would people with the capacity to create wealth bother doing so since it would inevitably be done at the expense of other things?Someone on €200,000 is liable to USC, PRSI and Income tax of €87,706. An effective tax rate of 43.85%.
Someone on €40,000 suffers deductions of €6,428. An effective tax rate of 16.07%.
So the person earning 5 times as much income as the other, pays 13.6 times as much Income tax.