>you might make more money but despite that, you will not be able to buy more things.
I'm not sure how else to read that. If you make more money, you can buy more things. Even if you go up a tax bracket. If you make twice as much money and that moves you up a tax bracket, you won't be able to buy twice as many things, but you can still by more things than you could when you made half as much. Maybe 1.8 times more things.