Do you have any examples of countries where progressive taxation would be a hindrance for escaping poverty? This frankly sounds like a made-up argument against taxation.
Spain. There are levels of taxation that provokes the following: your small company (1 to 10 employees) is doing really well so you try to increase the number of employees and business. And what happens is that when passing some threshold you will have to pay the next level of taxes and end up earning less after taxes than when you were smaller. So we have a lot of small companies that cannot or don't want to take that risk.
Good example is UK. As a specialist you would be in area of 40% effective tax rate, but going over 50% is not uncommon (after IR35 changes some workers have to pay employer's NI) plus there are other taxes like council tax or high VAT.
I would think a specialist paying 40% in taxes has already escaped poverty? That's my confusion here, poverty suggests such a low income that progressive taxation shouldn't really affect yet.
The thing is that the costs of living are so high in cities that offer such pay, you can hardly save anything and if you started with 0, it will take decades to have some security. Sure you make a lot of money, but you are still essentially living paycheck to paycheck. My definition of poor is someone who doesn't have their own home or flat, savings that let them withstand at least a year of unemployment without having to use state benefits and so on.
