This covers federal income taxes only, excluding payroll taxes such as Social Security and Medicare. Including those the top 1% pays ~25% of all federal taxes while earning ~22% of all income.
Top 1% have more income (income inequality is a thing). Taking away 40% income would hit the bottom 99% much harder than it would affect the life of top 1%. 50% of renters spend >30% on housing, 25% spend >50%.
40% figure is also based on individual income taxes. It drops significantly if you consider other sources (payroll etc).
Top 1% also receive preferential tax treatment and benefits disproportionately from policy changes.
Income is what you earn from your labor (the things robots will do in the future). Capital is setting money to make more money (e.g., by buying robots to get rid of labor that earns income).
You're missing the point. The effective tax rate of many billionaires is lower than ours. "Musk with a fortune of $244 billion, paid an average effective tax rate of 24% from 2018 to 2020". In other years it was as low as 3%[2].
https://usafacts.org/articles/who-pays-the-most-income-tax/