So she's not wrong, but she'd only be hitting those numbers if she won a really big tournament or two.
Edit: I forgot that the self employment tax phases out at ~$120k labor income, so she'd need a lot of investment income (or a high earning spouse) to pay both the top marginal income tax rates and the and 15% employment tax.
Government policy should incentivize constructive industries.
Someone correct me if my figures are wrong, her total tax rate all-in (based on NYC), appears to be closer to 41%.
$1m gets you to ~48%. $10m gets you to ~56%.
Edit: I think you can't carry over losses from prior years, so if you lose money one year and make money the next, your taxes on your net earnings can be higher. Rule of thumb for professional poker players: If you don't have a profitable tax year, it is time to quit.