At least for me, even income taxes as high as 53% have not discouraged me from trying to make more money. They have made me consider moving.

At some level, certainly at 90%+, the most rational thing to do to make more money is to spend time lowering your tax bill, which is not a particularly beneficial way (to society) of making more money.

But I can't image anyone at an income tax level of say 10% is being actively discouraged from making more money? Like you need it to survive, so choosing to make _no_ money because of taxes seems like a very bad strategy.

Prices are set on the margins, the reason people are paid what they are is because even a relatively small change would cause someone to do something differently. Same theory as why we can be confident raising the price of something a few cents is likely to cause someone to change their decisions - if it wasn't, the seller would raise the price by a few cents.

It isn't obvious what a 10% across-the-market tax will do, but by the nature of prices they are always going to be set near tipping points so it probably is going to cause people to drop out of the workforce or reduce the amount of time they spend working. Maybe tip people into less productive jobs that pay cash. I dunno. How many people and how many hours is an open question but all your imagination is really telling you is that you don't deal with marginal participants in the workforce.