Progressive taxation cannot work with democracy. Not over the long run, at least.
The main point is that progressive taxation allows to have an asymmetric distribution of contributions. You end up with more people receiving and less people paying. So instead of voting to know what to do of their collective contributions, the majority votes to know what to do with others’ money. They become a collective form of dictatorship.
Moreover the whole concept is transforming the contribution to the costs of maintaining the government (whether or not we really need it is another problem) into a reward/punishment system. The problem is that it rewards those who have not produced a lot and punishes those who have produced. It is therefore, on the whole, an incentive to not be excellent, productive and generally an asset and not a cost.
By so doing the taxation eats away its efficacy, and that calls for either a spending reduction or a taxation increase. Given that in this system those taxed the more are minority and those receiving the spending the most are the majority, guess how the “democracy” will respond!