According to the IRS: From 2019 to 2021, New York State lost a total $53 billion dollars of adjusted gross income (AGI) of people that left the state. At a taxation rate combined state/local of 14.8%, this would represent a loss of tax receipts of $7.84 billion per year. This loss has been increasing every year.
The IRS also note that taxpayers leaving the state earn $30,000 to $40,000 per year more than taxpayers moving into the state. In Illinois, 28% of taxpayers leaving the state earn more than $200,000 per year.
In nature. this is called a death spiral.